Stefan Bengtson, Simon Conway Morris, Barry J. Cooper, Peter A. Jell and Bruce N. Runnegar
'
�...
•
� �
� '!'"
t .,
.. �� :;.;:;::; _ ..+ ..."., +-r -
• •
er
•
n
••
, -
•
-
c
_ _
--...... - ._... .. .. .
__
AAP
Early Cambrian fossils from South Australia
Stefan Bengtson, Simon Conway Morris, Barry J. Cooper, Peter A. Jell and Bruce N. Runnegar
Published by the Association of Australasian Palaeontologists Brisbane 1990
Contents Palaeobiological setting: the Cambrian explosion ........ Evolutionary diversifications Palaeoecology ........ Skeletal material ....... Taphonomy and preservation. Biostratigraphy ....... Biogeography .. ...... Extrinsic factors .. .... .. .. ... . . Biological classification of early skeletal fossils Stratigraphy .. ... .. Sel1ick HiIJ ............ KuJpara .............. Horse Gully, Ardrossan .. ... Curtamulka ............ Willochra, north of Mount Ragless Bunyeroo Gorge .. Mt.Scott Ra ....... Wilkawil1ina Gorge ... Wirrealpa. .. . ... . Biostratigraphy ...... Regional biostratigraphy International correlations Systematic palaeontology.
10 10 10 10 10 10 14 14 14 16 19
CYANOBACTERIA . . . . . . . Girvanella Nicholson & Etheridge, Obruchevella Reitlinger, 1948 . . Endoconchia Runnegar, gen.novo
20 20 20 23
.
.
.
. . . 1878. . .
�
2 3 4 4 4 5 6 6 6 7
Cambroclavus Mambetov in Mambetov & Repina, 1979 . . . . . . . . .
.103
TOMMOTIIDS ............... Eccentrotheca Landing et al. , 1980 . . . . Lapworthella Cobbold, 1921 . . . . . . . Camenella Missarzhevsky in Rozanov et al., 1969. . . . . . . . . . . . . . . . . . . . Kennardia Laurie, 1986 . . . . . . . . . . , Sunnaginia Missarzhevsky in Rozanov et al., 1969 . . . . . . . . . . . . . . . . . . . . Kulparina Conway Morris & Bengtson, gen. nov .. . . . . . . . . . . . . . . . . ' Paterimitra Laurie, 1986 . . . . . Tomotiid suprageneric taxonomy.
.119 .119 .121 .131 .133 .134 .136 .142 .142
ORNAMENTED CONES . ... Stoibostrombus Conway Morris & Bengtson,gen.nov
.145
SMOOTH CAPS.
.158
.
.145
SMOOTH CONES .. . . . .. . . Archaeopetasus Conway Morris & Bengtson, gen.novo ................. .
.160 .160
BIVALVED ORGANISMS OF POSSIBLE .... BRACHIOPOD A FFINITY Apistoconcha Conway Morris, gen.nov Aroonia Bengtson, gen.nov Discussion. ........
.164 .171 .181 .184
HYOLITHELMINTHS Hyolithellus Billings, 1871 Byronia Matthew; 1899. . .
.186 .187 .190 .190
SPICULES. .. . .. . ... . Remarks on Early Cambrian sponges Dodecaactinella Reif, 1968. . . . EifTelia Walcott, 1920. .. .. ... . .. Heterostella Fedorov in Shabanov et al., 1987 Nabaviella Mostler & Mosleh-Yazdi, 1976. Taraxaculum Bengtson, gen.novo Microcoryne Bengtson, gen.nov.
24 24 27 27 31 31 33 35
COELOSCLERITOPHORANS. Approaches to the study of Coelosc1eritophorans. Suprageneric taxonomy.
37
ANABARITIDS. ............. Anabarites Missarzhevsky in Voronova & Missarzhevsky, 1969 . . General discussion. .. . . .. . ..
39 39
DECOLLATING TUBULAR FOSSILS Actinotheca Xiao & Zhou, 1984.
.202 .203
45 45 48 51 54
HYOLITHS ........... Conotheca Missarzhevsky, 1969. Microcornus Mambetov, 1972 . Parkula Bengtson, gen.nov . . . Hyptiotheca Bengtson, gen.nov 'Hyolithes'. . . . . . . . . . . . . . . TriplicateIla Conway Morris, gen.novo
.211 .213 .216 .223 .228 .231 .231
MOLLUSCA .............. l\fackinnonia Runnegar, gen.nov .. . Leptostega Geyer, 1986 . . . . . . . . Pararaconus Runneger, gen.nov .. . Yochelcionella Runnegar & Pojeta, 1974 Stenotheca Salter in Hicks, 1872 Anabarella Vostokova, 1962 . . . . Proplina . . . . . . . . . . . . . . . . Kalbyella Berg-Madsen & Peel, 1978 Pelagiella Matthew, 1895 Yuwenia Runnegar, 1981 . . . . . .
.232 .233 .234 .234 .236 .243 .244 .251 .252 .252 .256
.
.
.
.
.
.
CHANCELLORIIDS... ... .. ... Composition of chancelloriid scleritome. . .. Cbancelloria Wa1cott, 1920. . . Archiasterella Sdzuy, 1969. . .. ... Allonnia Don! & Reid, 1965. . . . . . . . . Eremactis Bengtson & Conway Morris, gen. novo . . . .. . .. . . .. .. .. Structure and composition of chancelloriid sc1erites . . . .. .... .. . . Hippopharangites Bengtson, gen.nov .
.
.
.
.
.
.
.
.
57 61 63
HALKIERIIDS ............. Halkieria Poulsen, 1967 . . . . . . . . Tbambetolepis Jell, 1981. .. ... . Structure of halkieriid sc1eritorne ...... Functional morphology of halkieriid sc1erites Phylogeny of coeloscIeritopherans
69 71 78 97 100 100
CAMBROCLA YES
103
.
.
.192 .197
Beshtashella Missarzhevsky in Missarzhevsky & Mambetov, 1981 Pojetaia Jell, 1980. . . .. . . . . PROBLEMATICA . . .. . . . . Ardrossania Runnegar, gen.nov TRILOBITA. . . .. . . .... Serrodiscus Richter R. & E., Hebediscina Rasetti, 1972. Korobovia Jell, gen.nov . Egyngolia Korobov, 1980. Redlichia Cossmann, 1902 Abadiella Hupe, 1953 . . Eoredlichia Zhang, 1950. . Xela Jell, gen.novo YorkeUa KQbayashi, 1942 Onaraspis Opik.1967 . . Elicicola Jell, gen. nov . . Pararaia Kobayashi, 1942 Alanisia Hupe, 1953. . . Hsuaspis Zhang, 1957 .. Micmaccopsis Lermontova, 1940. Paleofossus Pokrovskaya, 1959. . Prouktaspis Repina in Repina & Khomentovsky,1965 Kootenia Walcott, 1889 . . . . . .
.
.
.
.
.
256 256 257 257 257 258 261 263 265 267 276 281 285 288 295 298 302 308 310 314 318 318 322
.322 .323 .325
CRUSTACEANS . . . . . . . . . Epactridion Bengtson, gen.nov Isoxys Walcott, 1890 ....... PROTOCONODONT . . . . . . . Protohertzina Missarzhevsky, 1973. Mongolodus Missarzhevsky, 1977
. . .S330 .330 . . . . . 331
INCERTAE SEDIS Microdictyon Bengtson et aI., 1981
.332
SPHERICAL FOSSILS OF UNCERTAIN AFINITY. . . . . . . . . . . . . Olivooides. . . . . . . . . . . . . . Aksuglobulus, Ambracbaeooides, Nepbrooides. . . . . . . . . . . Megabystricbospbaeridium. .. . ......... Arcbaeooides. Aetholicopalla Conway Morris, gen. nov
. 336 .336 . 336 . 338
ACKNOWLEDGEMENTS
. 343
REFERENCES
.345
APPENDIX
.361
.
.
.333 . 333
Early Cambrian fossils from South Australia STEFAN BENGTSON, SIMON CONWAY MORRIS, BARRY J. COOPER, PETER A. JELL AND BRUCE N. RUNNEGAR
BENGTSON, S., CONWAY MORRIS, S., COOPER, B. J., JELL, P.A., & RUNNEGAR, B.N.,
1990:7:19. Early Cambrian fossils from South Australia. Mem. Ass. Australas. Palaeontols 9, 1-364. ISSN 0810-8889. On Yorke Peninsula Early Cambrian sections in Curramulka Quarry, Horse Gully near Ardrossan, and on the Kulpara Road near The Hummocks and in the Flinders Ranges sections at the western end of Bunyeroo Gorge and in the Mount Scott Range have been systematically sampled. Their profuse biotas of sponges, algae, molluscs, trilobites, ostracodes, hyoliths, tommotiids, coelosc1eritophorans, anabaritids, and a variety of other small skeletal fossils are described. New genera erected are Endoconchia (cyanobacterium), Taraxaculum (sponge), Microcoryne (possible octocora]), Eremac tis, Hippopharangites (coelosc1eritophorans), Kulparina (tommotiid), Stoibostrombus (ornamented cone), Archaeopetasus ( s m o o t h c o n e ) , Apistoconcha, Aroonia (brachiopod-like bivalved organisms), Parkula, Hyptiotheca (hyolithids), Triplicatella (uncertain affinity),Mackinnonia, Pararaconus(mo11uscs),Ardrossania (possible mol lusc), Korobovia, Xela, Elicicola (trilobites), Epactridion (bradoriid), and Aetholicopal la (spherical, uncertain affinity). Trilobites from these and other sections in the same areas are used as the basis for a regional zonation of four zones. International correlation with China and Siberia is attempted but remains equivocal. Numerous biological inferences regarding the small skeletal remains are recorded and comments are made on palaeobiogeography, palaeoecology, and the' Cambrian explosion' of skeletal fonns.
Stefan Bengtson, Institute of Palaeontology, Box 558, S-751 22 Uppsala, Sweden; Simon Conway Morris, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge eB2 3EQ, United Kingdom; Harry J. Cooper, Department of Mines, South Australia, p.a. Box 151, Eastwood, South Australia, Australia 5063; Peter A. Jell, Queensland Museum, p.a. Box 300, South Brisbane, Queensland, Australia 4101; Bruce N. Runnegar, Department of Earth & Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90024-1567, USA; received 19 July 1989.
CAMBRIAN FOSSILS of South Australia and the sedimentary sequences in which they occur have been studied intermittently for over 100 years since Tepper (1879) recorded fossils from the Parara Limestone near Ardrossan on Yorke Peninsula. Subsequent important investigations were reviewed by Daily (1956) who simul taneously provided the most significant bio stratigraphic contribution to date; he nominated 12 'faunal assemblages' and the relationship of these units to several lithostratigraphic sections. His scheme has been widely quoted but little used by other workers, principally because taxonomic treatment of the faunas upon which it was based remain largely unpublished. Since 1956, contributions to our understanding of the Cambrian faunas of South Australia have been the series of geological maps covering most of the Cambrian outcrop areas of South Australia (Binks, 1968; Coats, 1973; Crawford, 1960; Dal gamo, 1982; Dalgarno & Johnson, 1964, 1965, 1966; Thomson, 1969; Thomson & Horwitz, 1962), several general papers including Daily (1969, 1972, 1976), Daily et al. (1982a,b), Dal-
garno (1964), Jago et al. (1986), Moore (1983), Wopfner (1970) and Youngs & Moorcroft (1982), and faunal studies on trilobites (Conway ¥orris & Jenki ns,1985; Jago e t al.,1984; Opik,1975b; Pocock,1964, 1970,1974), ar chaeocyathids (Debrenne, 1969, 1970,1974a, b; D e b r enne & Gr a v e s to c k, 1 9 9 0 ; Gr a v e s t o c k,1 983,1984; Wal ter,1967), m ol l u s c s (Jell,1980; Runnegar,1983,1985a; Runnegar & Bentley, 1983), organic-walled microfossils (Foster et al., 1985) and other fossils (Bis choff,1976; Brasier,1976; Glaessner,1979a; Jell,1981,1984; Runnegar,1985b). The study reported in this Memoir has been aimed at detailing the taxonomic basis for biostratigraphic subdivision and international correlation. Relative to total Cambrian outcrop only a few areas (Figs 1,2) have been investi gated; all or parts of the biotas have been described in detail for 13 sections of various thicknesses (Figs 3-7). We hope that future dis coveries in all the Cambrian outcrop areas will fill gaps in this sequence of faunas and comple ment the current presentation.
2
STEPAN BENGTSON et al.
Palaeobiological setting: the Cambrian explosion T h e a b r u p t a p p e a r a n c e , c l os e t o t h e Precambrian-Cambrian boundary, of hard skele tal parts in metazoans, protists, and cyanobac teria, combined with a striking increase in the diversity and relative complexity of trace fossils, provides strong evidence for major adaptive radiations, the 'Cambrian explosion' (Bras ier,1979; Conway Morris, 1987). This evolution ary episode poses a number of questions, to which the richly fossiliferous sequences in the Lower Cambrian of AustraHa provide some answers. In terms of skeletal remains, Lower Cambrian faunas are typified by archaeocyathans, sponges, b ra c h i opod s , e c h i n o d e r m s , t r i l o b i t e s , ostracodes, molluscs, hyoliths, tommotiids, coeloscIeritophorans, anabaritids, and a variety of other sma}) skeletal fossils. Because of bios tratigraphic uncertainty, order of appearance of these groups is difficult to establish. In this paper, representatives of all these groups are considered in varying detail, with the twin exceptions of the archaeocyathans, which have received rather ex tensive attention (see Gravestock,1984 for refer ences to earlier literature), and the brachiopods, w h i ch r e m a i n almost unstudied (Laurie, 1986,1987).
Evolutionary diversifications During this adaptive radiation extant phyla arose (e.g., sponges, molluscs, brachiopods, and echinoderms) along with a remarkable variety of geologically short-lived groups that cannot readily be placed in familiar phyla and yet are so distinct from one another that taxonomists may regard them as separate phyla. This burst of diversification and apparent weeding-out of many forms raises questions that cannot yet be satisfactorily answered. 1, does the rise of so many novel forms indi cate the operation of evolutionary mechanisms different to those usually invoked during specia tion (Erwin & Valentine,1984), or is it due more to opportunistic occupation of an ecological vacuum? Our work provides further evidence of the extent of this diversification, but little new light on the possible processes involved. How ever, it seems that in some groups, especially the tommotiids, there is a continuity of morphologi cal forms that link seemingly different end-mem bers. Thus, while the origins of the tommotiids
are not known, evolution within the group may have entailed only minor genetic changes. 2, is it possible to ascertain the inter-relation ships between presently enigmatic groups and so erect a more satisfactory scheme of classifica tion? Major groups documented here include the coeloscleritophorans, anabaritids, cambroclaves and tommotiids. However, none can be clearly related to each other or to known phyla, and their ancestries are obscure. In addition, there are other groups, generally represented by one to a few taxa, whose affinities are equally uncertain. 3, what was the rate of metazoan diversifica tion during this interval? Given uncertainties of clas sifica t ion, regional correlations, and proposed radiometric time scales, any estimate is f r a ught w ith p r ob l ems. H o w e v e r , if the Precambrian-Cambrian boundary is substantial ly younger than previously thought (Odin et al., 1985; Conway Morris,1988), then rates of diver sification were more rapid than indicated by earlier compilations (e.g., Sepkoski,1981).
Pa laeoecology The lack of living representatives of many early skeletal groups makes autecological analysis dif ficult. Inferences may be obtained from mor phological analogies with forms of known e cologicaJ habits, and from functional mor phological considerations. Suspension feeders close to the sediment/water interface appear to have been numerica1ly abundant. They are rep resented by sponges, archaeocyathans, sedentary tubular fossils (hyolithelminths, anabaritids), brachiopods and brachiopod-like animals (Apis toconcha and A roonia) , bival v e molluscs (Pojetaia), and echinode rms. Hyoliths are generally regarded as deposit feeders due to the occasional preservation of a sediment-filled gut (Runnegar et a1.,1975), although this may not be valid as a generalization. Monoplacophorans and gastropods probably mainly included deposit feeders and grazers, and to these categories per haps belonged halkieriid coeloscleritophorans and tommotiids, interpreted as sluggish crawlers (Bengtson, 1970; Jell,1981; Bengtson & Con way Morris, 1984). Predators are represented by Protohertzina ( c f. Be n g t s o n , 1976,1 9 83; Szaniawski, 1982), and possibly also by oc tocorals (Microcoryne?). The abundance of sclerite- or spicule-bearing metazoans, and une quivocal evidence for a tightly integrated scleritome in the halkieriids and carnbrocIaves suggest the need for protection, presumably against predators.
3
EARLY CAMBRIAN FOSSILS, S. AUST.
GULF ST. VINCENT
, I
I 36°E
LAKE
30"S
,. CopJey , ...-!
'l�
, Blinman :�aWker Port Augusta CURRAMULKA QUARRY SECTION�
•
Q
\ �I Port Lincl\o� ln
•
NMVPL95 o
Burra
FROME .
I I 32°S
,
I I
Renmark 34"S
...-..
I
35°S
I
lkm
L...---I
o I
lkm I
While Point
I
Boxing Bay Hawk's Nest Bald Rock
KANGAROO ISLAND
Fig. 1. Locality map for sections on Yorke Peninsula and Kangaroo Island. Areas of Cambrian outcrop in South Australia shown in solid black on background map at scale of 1 :8,000,000. Roads shown as solid, mostly straight lines. Skeletal material As in younger marine faunas, three principal skeletal compounds (calcium carbonate, calcium
phosphate, and silica) were employed by Early Cam b rian metazoans. Silica is most charac teristic of spo nge spicules. The apparen t prevalence of phosphatic skeletons amongst the
4
STEFAN BENGTSON et al.
small shelly faunas has led some investigators (e.g. Lowenstam & Margulis,1980) to propose that they were unusually important in compari son with later biotas. However, it is clear that a phosphatic composition is often a result of diagenetic replacement or overgrowth of an originally calcareous shell. The proportion of taxa with original calcium phosphate does not appear to have been significantly higher than subsequently. Because of our inability to trace lineages, it is not clear how many times the ability to secrete hard parts arose. However, in our material, tom motiids, protoconodonts, hyolithellids, Micro dictyon, Stoibostrombus, and the bradoriids probably acquired phosphatic skeletons inde pendently. Of groups with calcareous skeletons, sponges, trilobi tes, and echinoderms are presumed t o have had a high-Mg calcite skeleton. Primary crystallographic structure is sometimes preserved in these groups while in ternal moulds of molluscs and brachiopod-like organisms may preserve imprints of crystal fabric, making it possible to identify original a r a g o n i t e and cal c i te (Runnegar, 1 9 8 5 b; Fig.159). Of the remainder (e.g. coelosclerito phorans, cambroclaves, anabaritids) the car bonate polymorph employed is more conjectural. Their ubiquitous recrystallization, where trilobite cuticles and echinoderm ossicles are preserved in original calcite fabric, suggests, however, that they had a primary aragonitic composition. Taphonomy and preservation The prevalence of phosphatized shells in the Lower Cambrian is one aspect of the major episode of phosphogenesis close to the Pre cambrian-Cambrian boundary (Cook & Sher gold, 1984,1986). The final trapping of phos phorite accumulations often entails transport and concentration of material (Southgate, 1986). Detailed petrographic work is requ ired to elucidate the taphonomy of early skeletal fossils, especially the timing and selectivity of phos phatic replacement or overgrowth. The related possibility of reworking and the formation of condensed horizons is also of biostratigraphic significance. Biostratigraphy Understanding the 'Cambrian explosion' re quires detailed biostratigraphic correlation. However, although local zonations have been established, convincing inter-regional correla tions remain difficult (below). While these problems may be a reflection of parochial
taxonomy, other problems seem to be due to some taxa having lengthy stratigraphic ranges, while the endemics often have apparently shorter ranges. The bases of the fossiliferous sections examined herein are correlated with Atdabanian faunas elsewhere. Thick sequences (e.g., Mt Ter rible Formation and Wangkonda Lst.) in the Mt Lofty Ranges (Adelaide region) are believed to be older than the units examined here (Daily, 1976), but have been subject to only cursory study by us. While our studies are not immediately relevant to discussions of a boundary stratotype, greater stratigraphic range of some fossils, especially the anabaritids, s tresses the need for precise taxonomic work. Biogeography Lower Cambrian biogeographic provinces have been based on trilobites (Cowie,1971) or aT chaeocyathids (Debrenne & Rozanov,1983). Whatever the accuracy of those schemes at tempts to utilize small shelly fossils in this con text (Jiang,1984b) must be regarded as highly speculative given the state of their taxonomy. Palaeomagnetic work indicates a proximity be tween Australia and south China during the Lower Cambrian (Lin et al.,1985). Extrapolation of facies belts between the two regions and jux taposition of the two cratons at similar subtropi cal latitudes might suggest similar faunas but current studies (Qian & Bengtson, 1989; Con way Morris & Chen, 1989, 1990b, in press) indicate that overal1 similarities are not striking in a p parently coeval faunas. Indeed, t h e strongest similarities of the Australian small skeletal fossils might be with assemblages in Mongolia (Voronin et al.,1982) and Kazakhstan (Missarzhevsky & Mambetov, 1981). Trilobite distributions were analysed by Cowie (1971) for the Early Cambrian and by Jell (1974) for the Middle Cambrian; both indicated 3 faunat provinces of roughly similar extents. Both included Australia, Siberia and China in the same faunal province and the trilobites described herein strongly support that point of view. Ap proximately half the 30 taxa noted have generic affinities with Siberia, and a similar number, though not all the same ones, have generic af finity with China, particularly southwestern China. The single species in common with each of Spain and Alaska in different faunal provinces are likely widespread taxa and not as significant as the overwhelming similarities with Asian faunas of the time. An objective analysis of Early Cambrian trilobite distributions based on total faunas is needed to be more explicit, but that project is outside the scope of this work. In view
F EARLY CAMBRIAN FOSSILS, S. AUST.
•
5
Burra
o Ikm '----'
\
o l
\ \ \
1 km , I
\ \ \ \
Fig. 2. Locality map for sites and sections in the Flinders Ranges; clockwise from the bottom right they are\be Willochra area, Bunyeroo Creek section, WirreaJpa area, Mt. Scott Ra. area, and Wilkawillina Gorge area. Areas ofCambrian outcrop in South Austra1ia shown in solid black on background map at scale of 1:8,000,000. Roads or tracks shown on insets as dashed lines.
of the trilobite information it appears that the distinction in the small skeletal faunas of south China may be due to differing local effects rather than major faunal distinctions.
Extrinsic factors During the 'Cambrian Exp1osion' the role of
changes in ocean chemistry for the evolutionary history of skeletal acquisition and modification is obscure (Railsback & Anderson,1987). Brasier (1986a) suggested that one might be able to trace a course of sequential mineralization as different p olymorphs and minerals wer e 'favoured' by prevaiHng conditions. Given the prob1cms of correlation such a sequence may be
-
6
STEFAN BENGTSON
et
al.
difficult to recognize, and may in any event be difficult to reconcile with their co-existence from the Lower Cambrian to the present day.
Ranges, and in the Flinders Ra�ges as well as in . adjacent areas to the west (Dally m Cooper & Grindley 1982). Num'erOlis subsurface occurren ces have lso been recorded from as far afield as the eastern Officer Basin (Jago & Youngs,1980) and the eastern Arrowie Basin (Youngs & . Moorcroft,1982). With the exception of the Ka!1mantoo Group, these Lower Cambrian depOSIts generally consist of thin silicicl�stics overlain by . Although early skeletal faunas include major , thick carbonates reflectmg environments whIch groups such as the molluscs, hyoliths, chaetog range from supratidal to marine shelf. DeeI?water naths (represented by the protoconodonts, �ee clastic deposition (Kanmantoo Group) In the Szaniawski,1982,1983) and sponges, a wide southeast of the State has been interpreted as diversity of enigmatic forms also occurs. Their accumulation at a continental margin developing documentation may shed new light on the early at that time and resulting from continental diversification and ecology of metazoans, but breakup (von der BOTch,1980). this goal is still far from attained. Depocentres of Lower Cambrian shelf car Apart from fragments Of tubes (e.g. Phyl o bonate sedimentation include the Stansbury . chites involotus Qian & Ym,1984a, pJ.6, figs (Yorke Peninsula, Mt. Lofty Range�), 0wie 1-4), sometimes with their ends dilated by (Flinders Ranges) and OffIcer BaSInS ( Ig.l). mineral growth (e.g. Rhabdochite� exasperatus These sediments form part of the Cambnan to He in Xing et al.,1984b, pl.15, fIgS 14-20; R. Devonian depositional phase in South Australia scissus Yang & He,1984, p1.3, figs 1-5), prob (Wopfner,1972). Where adequa!e dat� are avail able fragments o f t ri lobite (e.g., Yang & able in the Stansbury and Arrowle BaSInS, Low7r He,1984, p1.2, fig.8, as Fomitchella inchoat�) Cambrian sediments unconformably overlIe and other unidentifiable material, most Il Proterozoic deposits and in most places are over lustrated 'small shelly fossils' appear to repre lain conformably by marine carbonates and sent 1, disarticulated sclerites and spicules, 2, paralic red beds. On Kangaroo Island and in the tubes, or 3, cap-shaped shells. The first category Mount Lofty Ranges, Lower Ca"?brian ca: presents particular problems, but rare examples Donates are succeeded by the thIck clastIc of articulated sclerites in halkieriids (Bengtson deposits of the Kanmantoo Trough. Parts of the & Missarzhevsky,1981; Bengtson & Conway Arrowie and Stansbury Basin sequences and the Morris,1984) and cambroclaves (Mam etov & entire Kanmantoo Trough were significantly Repina, 1979; Conway Morris & Chen,ln "r�ss; folded during the Late Cambrian-Early Or Fig.68) assist in sc1eritome reconstructIon. dovician Delamerian orogeny and today form Taxonomic treatment of sclerites must employ part of the Adelaide Fold Belt. the various criteria (e.g., co-occurrence, similar micromorphology etc.) applied to scleritome Sellick Hill reconstruction in the conodonts (Bengtson, 1985a).· Attempts at scleritome reconstructions The section at SeHick Hill, south of Adelaide, lies from the literature are often frustrated by the within the Stansbury Basin and forms part of the paucity of illustrat on� and sOJ;netimes � ack ?f Delamerian F o ld Belt having u ndergone precise stratigraphlc InformatIon. SuffIcIent d metamorphism to the level of the biotite zone lustration of sclerite variability is essential, be (Offler & Fleming,1968). As a consequence fos , cause specific differences may only become sils are poorly preserved In the 37 samples sys apparent when a large suite is compare , even tematically collected from topmost M0':1nt though individual sclerites of either species may Terrible Formation, Wangkonda Lst., Selhck be effectively indistinguishable. Similar com Hill Formation and basal Fork Tree Lst. The ments also apply to cap-shaped and tubular fos SeHick Hill section occurs within a steeply dip s i l s , a l t h o u g h p r o b l e m s o f s c l e rit o m e ping and overturned Late Proterozoic-Early reconstruction may not arise. Cambrian succession on the northern edge of a block upfaulted by Cainozoic tectonism (Daily et aI., 1982a). The fossiliferous nature of the sec tion was first widely recognized after the work of Howchin and David (Howchin, 1897). ru chaeocyathids have been described by Taylor Lower Cambrian sediments in South Australia (1910) and Debrenne & Gravestock (1990) and (Figs 1,2) principally outcr?p on Kangaroo Is the fauna compared with that from the Wilkawil land, on Yorke Peninsula, In the Mount Lofty lina Lst. at Wilkawillina Gorge. A trilobite from
�
Biological classification of early skeletal fossils
!
An: �
�
�
�
?
Stratigraphy
EARLY CAMBRIAN FOSSILS, S. AUST.
v.> o
>l> Q
I
I
ttJ
� \J) t"11
�
• r' ......
� CJ1
metres
-<� 'V'
r' r' '-1 ...... CX>�
t"11
><
v.> 0:1
"t:l
a \J) c: �
••••
•
Zr' ...... �
CJ1 Q
cr-. Q
I
I
r'r'r'r' ,.......a� """""'� ��CX> � �\Og) ...... S
��
�
0 Z
'-1 0'.
��.
•
Z � -< 'V
r'
\0 CJ1 .",
tr:1
t"11
......
." t"11
�
a \J) c: �
•
Eiffelia araniformis
•
Pentact spicules
•
Hexact spicules ••
•
"t:l
a
Obruehevella de/ieata ArchtastereIla hirundo Allonniacf. tripodophora
•
•• ••
•
a
Girvanella s p .
• •
'-i
t"11
• •
DodeeaaetineIla eynodontota Clove-shaped spicuJes
• •
Polyactine spicules
•
•
••
•
•
•
•
•
•
•
•• •
•
•
•
Thambetolepis
•
Halkieria parva Hippopharangites dailyi Eremactis mawsoni Chancel/oria racemifundis Chancel/oria spp.
----
delicata
•
•
•• •
•
•
•
•
•
•• •
•
•
•
1111
1111
1111
Lapworthella faseicu lata Stoibostrombus crenulatus
•
Smooth caps (form
•
•
•
•
•
Dalyatia macroptera Micrina elheridgei
•
•
•
• •
•
••
•
••
•
•
•
---•
••
•
IIIHIII
•
•
••
•
•
••
•
•
filiform is Torellella sp. Byronia? sp. AMicrodictyon depressum Aetholicopalla adnata Aroonia seposita . Triplicatel/a disdoma Actinotheca sp. indet. Hyptiotheca karraeulum
------
•
Hyolithel/us cf. micans Hyolithel/us
•
1111
A)
Anabarites trymatus
• •
7
'Hyolithes'
conularioides
Microcornus petilus Conotheca australiensis Hyolitha indet.
••
•
•
••
•
•
••
•
•••• • ••
•
•
•
•• •
•
•
Anabarel/a australis Pelagiella subangulata Pojetaia runnegari
•
Abadiella huoi Pararaia tatei Epactridion portax
• •
• • • •
•
•
• •
Inarticulata indet . Leptostega? corrugata Stenotheca cf. drepanoida
Isoxys sp. Bradoriina indet. Echinodermata indet.
Fig. 3. Range chart for fauna of Curramulka Quarry section. th� overlying Heatherdale Shale in this section (Jago et al., 1984) is apparently closely related to a new species of A tops being described by J.B. Jago and P.A. Jel1 and is accompanied by a large punctate bradoriid ostracode so allowing correla tion with the Oraparinna Shale in the Bunyeroo Creek Section of the Flinders Ranges. Acritarchs
from the Heatherdale Shale were described by Foster et al. (1985).
Kulpara The section near Kulpara on northern Yorke Peninsula is located on the western edge of the
-
8
STEFAN BENGTSON
et
al.
metres
Cl '" � I tri 1111lr1.tll1.J1.l1.rutJ'" nr1.nIIJ1..l1..nJ Z t1"-t1."-�n
.D..IJi.lll;L.C..<...."""'-" .. C'l
•
Endoconchia lata
•
Endoconchia angusta •
•
•
•
•
•••••
•
•
•
••
•
•
•
•
• •
• •
•
•
•
•
•
•
•
••
•
••• ••• •
•
•
•••
� •
•
• •
••
•••••
• •
• •
•
••
•••••
•
•
••
••
••
••••••
• • • •
•
•
•
•
•
• • •
Chancelloria spp . Dailyatia macroptera
___ 1I 11f--._-----I.HI.HIll r--J UI 1------.;._-1.. . .__ •• •
••
Archiasterella hirundo Allonnia cf. tripodophora E iffe /ia aranifor mis Hexact spicules Pentact spicules Dodec aactinel la cynodotl tota Clove-shaped spicules Microcoryne cephalata Polyactine spicules Spindle-shaped spicules Thamvetolepis delicata Halkieria parva Halkieriidae indet . Hippopharangites dailyi Eremactis mawsoni Eremactis conara Chancelloria racemifundis
•
M icrina etheridgei
L apworth ell a fasciculata Eccentrotheca guano Camenella re ti culosa Sunnaginia sp. A Kulparina rostrata Cambroclavus absonus Scaly spines
....... • • • 1----------------...
Stoibostrombu5 crenulatus Ornamented cones (form A) • Ornamented cones (form Bl • Ornamented tubes (form B) • Smooth caps (form B) •• • Ar ch aeopeta5u5 excavatus Anabarites sexalox • • f--------------I.I_-I.HI. � Ana harites trymatus . --------------------...,.. -.-,IIII H yolithe l lus cf. micans • f----..... • H yol ithellus fi liformi; TorelIella sp. • • • Smooth cusps •
•
• • I-------------II.H.I--�. ••
•
• •• • . .I_-I...........HI. • • I--- -----------I.... •
1-------------1......1_-1.1---_. •• • ••
•
••
....... -I... . --I......HI. • • ••
•
•
..........HI.
• I------------------I.HI.
•
•
•
•
••
•
•••
•
SpinulitlJeca? sp . Hypliolheca karraculum ' H yoli the s' canularioides Microcornus eximius Microcornus petilu5 Hyolitha indet.
. ... Inarticulata indet. . �.I_-I .I_----------..., . _--�.I_�.I_� ... I------------I.I_---�I_ •
Mackinnonia
• •
•
•
•••
•
••• ••
••
•
•••
• • •
••
•
•••••
• • •
•
• •
•
• f----
Actinotheell sp. A Actinotheell sp. indet.
•
• • 1-------------------.. •
Aetholicopalla adnata Apisthoconcha apheles Apisthoconcha celsa Apisthoconcha siphonalis Triplicatel/a disdoma Randomia sp . Actinotheea holocycIata Aetinotheea hernicyclata Actinotheca clathrata
••••
davidi Pararaconus staitorum Slenatheell d. drepanoida Anabarel/a lIus/ralis Pelagiella su bangulata Pelagieila adunea Yuwenia bentleyi
Besh tashella tortiUs Pojetai4 runnegari Ardrossania paveyi Pararaia tatei Yorkella australis Bradoriina indet. Echinodermata indet.
f---•
I----• •
1---•
EARLY CAMBRIAN FOSSILS, S. AUST.
9
KULPARA ROAD SECTION, YORKE PENINSULA
TOP OF EXPOSURE 105
• NMVPL94
100
• 6529RSl12-3,
•
-
•
NMVPL73 80
L
• 6529RSlll
• 6529RSllO
•
• 6529RS109, NMVPL96 60 • 6529RSI08
CJ) Q) ... ..... Q)
• 6529RSI07
I
I I
El
• 6529RS104-6,
•
•
••
NMVPL71 40
L1760, L1860
• 6529RSI03
• 6529RS102 • 6529RSI01
20
s.s
r
••••
I
PARARA LIMESTONE
• 6529RS100
• 6529RS99
o BASE OF FORMATION
Fig. 5. Range chart for fauna of the Kulpara Road section.
Delamerian Fold Belt. The sediments here are less altered than those at Sellick Hill, less deformed and with dips of 15-200 eastwards. Numerous horizons were sampled through the Parara Lst. at this locality where it is notably more silty than at the Horse Gully or Curramulka localities. Cambrian fossils, probably trilobites,
were first recognized from the Kulpara area by H�Y.L. Brown around the turn of the century and noted by Etheridge (1919). This site is also close to the original collecting localities of Faunal Assemblages 5,6 & 7 qf Daily (1956) and is the section from which Opik (1975b) described trilobites. Basal Cambrian siliciclastic sediments
Fig. 4. Range chart for fauna of Horse Gully, Ardrossan.
10
STEPAN BENGTSON et al.
(Winulta Formation) disconformably overlie upper Proterozoic (Adelaidean) deposits at Kul para and are overlain in turn by Kulpara and Parara Lsts. Horse Gully, Ardrossan Collecting localities at Horse Gully near Ar drossan and at Curramulka lie outside the Delamerian Fold Belt. The Lower Cambrian deposits are thus only very broadly folded. The succession unconformably overlies Lower Proterozoic crystalline rocks of the Gawler Craton. Over most of Yorke Peninsula, Cam brian deposits are poorly exposed as a conse quence of low relief and surface calcrete formation. One of the best exposures occurs on the side of the deep valley known as Horse Gully and was first described by Tepper (1879). Here, gently dipping Kulpara Lst. is overlain discon formably by type Parara Lst. The Kulpara Lst. contains an interval of abundant Archaeocyatha near its top which was assigned by Daily (1956) to his FaunaI Assemblage 2. The KuIpara Lst. at this locality correlates with the Wangkonda Lst. and SeHick Hill Formation at SeHick Hill (Debrenne & Gravestock, 1990). The dark blue grey Parara Lst. outcrops intermittently above the Kulpara Lst. on the side of Horse Gully. Faunal Assemblages 3 and 4 of Daily (1956) have been determined. The Parara Lst. here probably correlates with the upper Fork Tree Lst. and the overlying Heatherdale Shale of Sellick Hill. It recently yielded the bivalve Pojetaia run· negari Jell, 1980 and the coeloscleritophoran Thambetolepis delicata Jell,1981. Curramulka The quarry at Curramulka provides a good sec tion, c. 31m thick, within the Parara Lst. Al though no lithostratigraphic boundaries are exposed, it has been estimated that the oldest beds in the quarry are c. 47m strati graphically above the base of the Parara Lst. Cambrian fos sils were first recorded from this area by Fletcher (1890) and it is the type locality for most of the species described by Tate (1892). From subsur face investigations by Daily (1972), both the Kulpara and Parara Lsts may exceed 300 m in thickness on Yorke Peninsula. No single outcrop section collected here exceeds 90 m. Willochra, north of Mount Rag/ess The Early Cambrian succession at Mt Ragless
occurs in a steeply dipping syncline within the Delamerian Fold Belt in the southern Arrowie Basin. This small outlier was first recorded by Daily (1956) and subsequent mapping by Webb & von der BOTch (1962) and Binks (1968) deter mined Early Cambrian Parachilna Formation, WilkawiIIina Lst., Parara Lst. and Oraparinna Shale overlying a Late Proterozoic succession. Daily (195 6 ) recognized h i s Faunal A s semblages 1, 2 and 4 in the area. Bunyeroo Gorge The Early to Middle Cambrian succession in the Arrowie Basin outcrops along the western side of the Delamerian Fold Belt in the Flinders Ran ges and a good section is exposed in Bunyeroo Creek west of the gorge. The Early Cambrian section was first described by Dalgamo (1964). The top of the Parara Lst. and the Oraparinna Shale were sampled and yield an abundant fauna of trilobites as well as molluscs and other groups. A species of A tops apparently similar to that from the Heatherdale Shale (Jago et al.,1984) south of Adelaide occurs in the Oraparinna Shale. Mt. Scott Range Early Cambrian deposits at Mt. Scott Ra. are located north of Bunyeroo Gorge in a little deformed part of the Delamerian Fold Belt. Samples were collected from a number of creek sections of Ajax Lst. in this area, but most impor tantly from Section M of Gravestock (1984) who described the Archaeocyatha. This region was first mapped by Parkin & King (1952) with sub sequent detailed description of the Early Cambrian section by Daily (1956. 1972) and Gravestock (1984). The section dips c. 45° north east at this site and includes Faunal Assemblages 1, 2, and 3 of Daily (1956). The Early Cambrian sequence commencing with the Uratanna For mation followed by the Parachilna Formation, Ajax Lst. and the Billy Creek Formation uncon formably overlies Late Proterozoic sandstones and quartzites. The Ajax Lst. has been correlated with the WilkawilHna Lst. and the Kulpara and Parara Lsts in the Stansbury Basin. Wilkawillina Gorge At Wilkawillina Gorge, an Early Cambrian Ar rowie Basin succession consists of Woodendina Dolomite, Wilkawillina Lst. (including 4 mem bers), Parara Lst. (including three members), Bunkers Sandstone and Oraparinna Shale in a
Fig. 6. Range chart for Cambrian fauna of part of the sequence in the Mount Scott Range.
EARLY CAMBRIAN FOSSILS, S. AUST .
...... 0 0
..... (}"I 0
I
metres
I
c·
.!..r
88 ::l�
or 00;; t""0\ a (}"I
� :j
:> '--C :> >< t'-i
� t'I1
rJ')
�
�
0 Z
0
t'I1
•
N 0 0
N (}"I 0
I
•
r ......
�r ...... 00 0\
� r .....
•
r ..... 00 0\
.:'I
r .....
•
•
��� '"l:l'
rr
•
r ..... 00
tj
I
•
• • • •
• -----•
•
•
•
•
•
• •
• •
•
•
•
• • •
•
• •
1111
•
•
•
• •
•
• •
• •
• •
•
• •
•
•
•
•
• •
•
•
• •
1111
Polyactine spicules • • • •
•
•
•
Micrina etheridgei •
•
•
•
•
•
•
•
• •
•
• •
• •
• •
•
•
Torellella sp.
•
Byronia? sp. novo A
•
Protohertzina cl. siciformis
•
Mongolodus cf. rostriformis Microdictyon depressum
•
Aetholicopalla
•
Apisthoconcha apheles Aroonia seposita
•
Triplicatel/a disdoma Actinotheca sp. indet . Spinulitheca? sp.
•
Hyptiotheca
'Hyolithes' conularioides Microcornus petilus
•
•
•
•
•
• •
•
•
•
•
1nl
•
•
Stoibostrombus crenulatus Omamented cones (form C) Omamented tubes (form C) Archaeopetasus excavatus Anabarites sexalox Hyolithellus cf. micans Hyoiithellus filiformis
'--";111 •
Lapworthella fasciculata Cambroclavus absonus
•
•
• •
Chancelloria spp. Dailyatia macToptera
•
•
Spindle-shaped spicules Thambetoiepis delicata Halkieria parva Hippopharangites dailyi Eremactis mawsoni .Eremactis conarJl Chancelloria racemifundis
•
•
cynodontota
Clove-shaped spicules
•
•
1111
ArchiastereIla hirundo AlIonnia cl. tripodophora £iffelia araniformis Hexact spicUles Pentact spicules Taraxaculum volans
Microcoryne cephalata
•
1111
•
�
•
•
•
:j
•
-
•
��
Nabaviella sp.
•
•
en,
Dodecaactinella
------
Ill!
t'T1['Tj
"t1 a
�
•
� � C')C')
�
.....
• • •
'"1-.1S: t:'""'J Zc.n tJn t'T10 �"'"'l c.n'""'J ��
"tI
�� '"l:l.0 �r
(;J,:-'
00 0\ \0
•
•
-l a
zr
rr � ......
..... ..... (}"lOO o'l
00 0\ 00
(;J 0 0
I
Czc
adnata
karraculum
1111
•
•
1111
•
•
•
•
•
•
•
Hyolitha indet.
•
•
•
•
•
•
Inarticulata indet.
•
•
•
Mackinnonia
•
•
•
•
•
•
•
•
•
• •
•
•
Stenotheca cf. drepanoida
•
•
Anabarella australis
•
•
Anabarella argus
•
• • •
•
• •
• • •
Pelagiella subangulata . Pelagiella adunca Pojetaia runnegari Abadiella
•
•
davidi
Leptostega? corrugata
• •
11
huoi
Pararaia tatei Eoredlichia
shensienensis
Isoxys sp. Bradoriina indet. Botsfordia sp. Echinodermata indet.
1j
"'tj
�,0
�.
� :;;0
Pl � (IQ � () ::r' Pl '"t ..... rJl
0' '"t .....
n�
o Z
.
��� �O
VJ VI o IZl
..r er
� �g 0 o
0 ......
IZl
_.
�
ci
�
o a" ..... ell '"t
�� >
'"t:l
�
c:: :::l Pl fJJ 0.. ell rJl () :l. a" ell 0.. :::r' ell
:::::0- � :::.. >
� :»
:»
C r
Abadiella huoi • Pararaia tatet - - - - - •
� ---.�
ell
'"t
en'"t:lP >
�
-.
t>-3:» �
-J -J '"t:l
l'> en� >:-3> > �
-------
Yorkella australis Pararaia tatel
•
-
-
-
-
•
C
<: t:l
:DC !r f)
l'>
�l' > �
El
:D
'"t:l
� t-c
0 C
�
�
§[' E;-0 � 'T1
oIL
�
�
-VI VI 0000 �VI '"t1
>0 :D:D
> �> s:
\D . 0\
-J W
• Elicicola calva Alanisia guillermoi - - - - - • Yorkella australis - - - - • Pararaia tatel - - - -
(
r@
0
�
>
A c
"'t:)
en'"t:l
�8 �S
:E
\0 .j::..
t-> en �s:� >
t-P >:-3> s:
>
Abadiella huoi (asDolerolenus sp. of opik,1975b) occursin this part of section in trench to north of road but not fo und during co llection of road section
�G > ::D >
•
0'1
� G: 8 �
t;; P
>:-3�
-
C)
�e �O' > �
> ::0
_
0 0
GC/)
.
•
. rJl
@
�
C:1
tI1 Z 0 � rJl
0 Z �
...
�t:
mC/) 0
z >
Abadiella huoi - - - - - • Pararaia tatei --- - - - • Redlichiidindet. 3 - - - - • . Eoredlichia shensiensis - -- ....
� t- p
��
� p t......
Z :»
::D5 �� G >c
\0 \0
0
�
VI VI VI \00000 0\0 00 �J--I.,J--I.
en> >:-3S: > 1''"t1 �
VI \0 VI )0-11
OJ OC ::oZ m-< mm A::D
. enO �� 0 m> �- 0 � 1'::::\ > l' '"t:l
_
� -L__________ _________
Pararaia bunyerooensis - - -- • Redlichiidindet. 1 Hebediscina yuqingensis - - - - - -. Serrodiscus gravestocki - - -- - - ... Pararaiajaneae- - - - -- - ... Atops sp. novo - - - - - - - . Kootenia diutina - - - - - - • Paleofossus? sp. indet. . - - -- -- -. Hsuaspis bilobata - -- - - - - -.
- - -.
•
- •
ent'Ii
• •
-
A > Z
� :-
. -J
�
-0
,Q'"t:l
O.
Egyngolia willochra - - . I. • Pararala ratei Redlichiidindet. 2 - - - •
C/)c C/)r > Zr -<
Hsuaspis bilobata - - - - - • Redlichia takooensis - - - - -. Balcoracania dailyi Pocock,1970. ' . .138°E Emuella po/ymera Pocock,1970 • � Emuella dalgarnoi Pocock,1970 - c
--------..,..
r
t""' en �
§5�@
O C)
J;
�
�
...... VI 00 o
I
VJ �
�}
� eJ, * ..., C .... � ..... =I
@ f) 0(3 �Z � � > @
� N
>-' VI
\!2JJ
•
EARLY CAMBRIAN FOSSILS, S. AUST.
WILKAWILLlNA
'I
®
WIRREALPABLlNMAN RD
......
�
o 0\. C') .
MOODLATANA FMN
• I
I , I I I I
WIRREALPA LST
I
BILLY
I
CREEK
cz\.
·
...
LAKE
Leigh
*
j �. �� TORRE
>I
S
•
*
•
Ornparinna
.
WIRREALPA 88 LST
ORAPARINNA SHALE 87
Hawker
®-...
-Quom
FMN
I
Wirrealpa � *�
Blinman.
I
•
jD
Copley
H
@
•
1592
WEST OF WIRREALPA SPRINGS ORAPARINNA SHALE
BUNKERS SST ·
I
!\
.ORAPARINNA SHALE
ort Wakefield
1599
Ardrossan
BUNKERS SST
1593 PARARA LST
WIRREALPA MINE
1513 1512 1591 � 1594 1511
-I
__ _
WILKAWILLINA LST
POUND
QTZlTE
Fig. 7.
(continued).
®
MOO DLATANA FMN
C,tek
� •
1
13
'11' \!..JI
14
STEFAN BENGTSON
et
al.
restricted graben on the eastern side of the Delamerian Fold Belt, with dips of 40-50° E. The succession was first described by Daily (1956) and Dalgarno (1964) and has bec,ome the type section for several Early Cambrian rock units. Daily's faunal assemblages 1, 2, 3, 8, and 9 were recognized here. Gravestock (1984) and Clarke (1986a,b,c) remapped and measured the section in detail.
Wirrealpa Early and Middle Cambrian sediments of the Arrowie Basin outcrop along a broad belt from Wilkawillina Gorge north to Wirrealpa and beyond. Howchin was the first to find the Cambrian faunas at Wirrealpa and passed two brachiopod species to Etheridge (1905) for description. The Wirrealpa Lst. fauna was desig·nated faunal assemblage 10 by Daily (1956). Dalgarno & lohnson (1964,1966) mapped this region of the Delamerian Fold Belt that is struc turally complicated by syndepositional faulting and brecciation. The Hawker Group is mainly biostromal limestone which is best referred to the Wilkawillina Lst. A number of trilobites are described from localities in the structurally com plex area around Wirrealpa Springs and although stratigraphic order is readily discerned, exact relationships between the small dislocated sec tions is not available.
Biostratigraphy Fossiliferous beds (with shelly fossils) in· the Cambrian of South Australia are few, with thick intervening barren units. This is particularly true for trilobite-bearing beds whereas small skeletal fossils are found in a considerably greater num ber of horizons. Moreover, diversity of the avail able shelly faunas is relatively low as opposed to the archaeocyathid faunas of the same areas. For these reasons the biostratigraphic suggestions made herein cannot be considered definitive but rather a progress report on the relatively small amount of collecting �arried out in this study. Regional biostratigraphy Trilobites. Their distribution in the 10 sections (1 composite) . collected (Fig.7) demonstrates that most trilobite faunules are of low diversity with a few localities containing five or six taxa but most yielding only one or two. Correlations are often founded on one or two taxa and fortunately
all except one of the faunules are recognized in more than one section. It is therefore possible to consolidate all the sections into one composite that represents the faunal sequence over the whole region (Fig. 8). With that achieved we have established four zones which have each been recognized in more than one section. Al though many more sections remain to be ex amined we introduce these zones in an effort to provide a scheme for more detailed work to proceed. We hope that future work will refine this zonation, fill in the obvious gaps and test its applicability to other areas. Such other areas as well as the Faunal Assemblages of Daily (1956) that were based on trilobites are discussed in relation to our scheme below. The three species of Pararaia belong to one evolutionary lineage and as they are not known to overlap in any section they probably represent three time intervals which we have designated as zones. The oldest, Pararaia tatei (Woodward), occurs in seven sections (Fig. 7) from Curra- . mulka in the south to the Mt. Scott Ra. in the north providing the best available correlation of the region. In the two sections just mentioned the Pararaia tatei Zone is preceded by theAbadiella huoi Zone. Of its fauna of five species, four occur in more than one section. The Pararaia tatei Zone begins at the first appearance of the nominate species. At NMV PL1498 the two most widespread species of the A. huoi Zone, E licicola calva gen. et sp. nov. and A. huoiChang, occur with P. tatei indicating overlap in the range of these taxa in the base of the younger zone. Whereas most sections exhibit mutually exclusive ranges for P. tatei as opposed to the older taxa, at least two, Hummocks and east of Wirrealpa Mine, show the overlap in the ·base of the younger zone. At NMVPL1499 a faunule of five species (Fig.7) is associated with large archaeocyaths in an extensive biohermal limestone. We have not collected this faunule at any other locality and consider that it may be ecologically restricted to biohermal structures. We, therefore did not as sign this faunule to a zone. Detailed mapping and sedimentology in the Wirrealpa Mine area indi cate that deposition of the platformal Wilkawil lina Lst. continued during deposition of the more basinal Bunkers Sandstone and Oraparinna Shale, and that the bioherms at NMVPL1499 postdate the Bunkers Sandstone (DJ. Graves tock, pers. comma 8 May 1990). Therefore on sedimentological grounds that faunule might be correlated with the P. janeae Zone but this is not verifiable palaeontologically. In the middle of the Parara Lst. is a thick section from which no trilobites are available to us. At the top of the Parara Lst. a single species I
EARLY CAMBRIAN FOSSILS, S. AUST.
of Pararaia and redlichioid fragments designate the P. bunyerooensis Zone. Whereas in the west on Bunyeroo Creek this horizon is only a small stratigraphic distance below the next zone in the . Oraparinna Shale, it is separated from that zone in the Wilkawillina Gorge section by the exten sive Bunkers Sandstone. A considerable time gap could therefore be inferred between the P. tatei Zone of the lower Parara Lst. and the P. janeae Zone of the Oraparinna Shale. Alterna tively the thick Bunkers Sandstone unit in the Wilkawillina Gorge section may reflect a phase of extremely rapid deposition (0.1. Gravestock, pers. comm., 8 May 1990) so that the time gap between the zones i s u n ce r t a i n . T h e P. bunyerooensis Zone is the least obvious of the zones as it is based essentially on the one nominate species and so it should be treated as provisional until the faunas of that interval are better known. In the Bunyeroo Creek section a faunule of seven trilobites represents the P. janeae Zone. Hsuaspis bilobata Pocock,1964 occurs with the nominate species at NMVPL1589 but is found at the higher horizon of NMVPL1595 on its own. We therefore include the range of H. bilobata within the zone, acknowledging that other localities where H. bilobata occurs without its associates at NMVPL1589, may represent the upper part of the zone. Indeed for convenience the range of Hsuaspis is included in this zone with the caution that more detailed work in this part of the column may lead to subdivision in the future. This zone is represented in the White Point Conglomerate and Emu Bay Shale on Kan garoo Island by faunules containing H. bilobata and several other species (Fig.7); because Bal coracania dailyi on Kangaroo Island is almost certainly a synonym of B. flindersi from Bal coracana Creek in the Flinders Ranges, the lower part of the Billy Creek Formatiori up to the horizon of the latter species is here assigned to the same zone. Faunas from western N.S.W. containing H. bilobata of Opik (1975b; but see discussion of this record below) may also be assigned here. Further up the section two species are iden tifiable from isolated horizons (Fig.8) near Wir realpa. The Redlichia guizhouensis horizon has been widely correlated through the Flinders Ran ges (Daily,1956), but we have found identifiable fossils at only one locality within the Wirrealpa Lst. so refrain from introducing any formal b iostratigraphic name. L ikewis e Onaraspis rubra sp. nov. is no t found othe r than at NMVPL89 and in Ten Mile Creek (by J. Clarke) in the Moodlatana Formation. This genus is else where in Australia knq.wn only from the Red lichia chinensis Zone (Opik's (1967) Ordian). It
15
would not be reasonable, therefore, to suggest a younger age for this species of Onaraspis. The Wirrealpa Lst. should then be considered to be of Early Cambrian age and pre-R. chinensis (or pre-Ordian). Of Daily's (1956) faunal assemblages, FA4 equates with the P. tatei horizon whereas FA3 equates with the earlier A. huoi Zone as it con tained Yorkella australis and Abadiella huoi which Daily (1956) mistakenly considered to be one specIes. Daily (1956) gave few clues to the faunal composition of assemblages FAS 7 which he identified in the Hummocks section, so our inter pretations of his assemblages as they apply to our collections are conjectural. However, he· men tioned that a trilobite of 'FAS is possibly repre sented in the Mount Scott Range area'; the common trilobite in the Mount Scott Range is A. huoi which is known to occur in the Hummocks section although described as Dolerolenus sp. (Opik 1975b). He further-mentioned that in FA? occurred a trilobite with 'some resemblance to Micmacca Matthew'; we consider it likely that this refers to the unsilicified specimens of Yorkella australis at NMVPL96 with broad blunt glabellar anterior. Elicicola calva of NMVPL73 is a less likely possibility. If these guesses are correct then FA5 is in the lower part of the P�uara Lst. from where we did not collect any trilobites. FA6 is represented by E. calva at NMVPL71; a nd F A 7 is r ep resented b y the f a una of NMVPL96. It seems unlikely that Daily col lected the upper part of the section as he would have instantly recognized P. tatei from his FA4. From these possible deductions it becomes ap parent that FA5 and 6 are roughly equivalent to FA3 and FA7 is just slightly older than FA4. The A. huoi and P. tatei Zones are contained in the Wilkawillina Lst. in the more northerly Wir realpa and Mt. Scott Ra. (Ajax Lst. is equivalent to Wilkawillina) areas but to the south near Wil lochra and on the Yorke Peninsula they are con tained in the Parara Lst., not the Kulpara (probable Wilkwillina equivalent); this indicates contemporaneous development of deeper water Parara Lst. and shallow platformal Wilkawillina . Lst. in parts of the Artowie Basin. Molluscs. In South Australia, Yochelcionella chinensis and Pojetaia runnegari occur in the P. janeae Zone at UNEL1764, and P. runnegari,. Pelagiella adunca, a n d· Anabarella c f . drepanoida are common in the A. huoi and P. tatei Zones. Pojetaia runnegari at the top of the dolomitized basal section of the Ajax Lst. in the Mt. Scott Range (UNEL1778; Runnegar & Bentley,1983) is no older than the only ·other known Early Cambrian bivalve Fordilla Bar rande (Pojeta,1975), but both are significantly -
16
STEFAN BENGTSON
et
al.
younger than the oldest occurrences of Watso runnegari a pp e a r s j u s t a b o v e t h e l o w e r nella. dolomites of the Ajax Lst. in Mt. Scott Ra. (Run Some stratigraphic differentiation in the mol negar & Bentley,1983), but apparently substan luscs may be provided by Anabarella argus low tially later at both Curramulka'(where it is rare) in the Ajax Lst. at UNEL1778 and UNEL1869 and Horse Gully (no records from Kulpara). and Anabarella australis at higher horizons Microdictyon depressum appears relatively early at equivalent-aged horizons at Mt Scott and Cur (UNEL1872,1873,1876). It may also be sig nificant that Yochelcionella has not been found ramulka, but is not known until later in Horse beneath the P. janeae Zone; most well-dated Gully. Notwithstanding the proposed derivation occurrences of Yochelcionella are of latest Early of Anabarites trymatus and A. sexalox along a to early Middle Cambrian age. Thus it is ex peramorphocline (Fig. 132), stratigraphic data pected that the biostratigraphic resolution of the offer little direct support. The earliest occurrence molluscs will improve as sampling intervals are is at Curramulka (asA. trymatus), although sup decre-ased. posedly equivalent-aged beds have yielded no Small skeletal fossils. Small skeletal fossil anabaritids. The oldest occurrence of A. sexalox faunas have been investigated from Sellick Hill, may be at Horse Gully where it appears at the Curramulka, Ardrossan, Kulpara, and the Mount b a se of the Pa rara Lst. Howev er, h igher Scott Range (Figs 3-6). In each of these, except (UNEL1852, 1853) in this section A. sexalox is accompanied by A. trymatus. In the Mt. Scott Ra. the first, the -trilobite zonation of the Abadiella huoi ZonefQllowed above by the Pararaia tatei A. sexalox appears near the top of the section, but Zone, with the latter zone near the top of each A. trymatus is apparently absent. section, provides a biostratigraphic framework. Although local diastems and discontinuities Support for correlation of the base of the upper are abundant in all sections, the break between the Kulpara and Parara Lsts at Horse Gully may zone as a reliable time line comes from as semblages shared between the upper Ajax Lst. mark a major hiatus as based on the stromatolitic horizons, iron enrichment and extensive phos (Mt Scott) and Parara Lst. These include Cambroclavus absonus and Apistoconcha, al phatization. This notion is reinforced by the major faunal changes that occur in the vicinity of . though unfortunately the specific identity of the latter is not certain at Mt Scott. this horizon. The upper parts of the sections at Horse Gully Becausethe Sellick Hill sections received only and Kulpara are correlated using Apistoconcha . cursory study, our comments are tentative. The first appearance of Dailyatia in the Sellick Hill apheles and Actinotheca holocyclata, and the a b s e n c e o f t h e s u c c e e d i n g Apistoconcha . Formation may correlate to the same event in siphonalis andActinotheca clathrata at Kulpara; Horse Gully, butin the Curramulka and Mt. Scott Ra. sections its first appearance almost certainly Archaeopetasus undulatus also supports this cor relation. Nevertheless, Kulpara has several en predates the base of our sections. Sunnaginia is demic taxa. unique to the Sellick Hill Formation and Fork Support for correlation of the A. huoi Zone Tree Lst., but in Horse Gully the abundance of closely related tommotiids (Kulparina, Ec may come, although they do not coincide exact ly, from the consistent separation between centrotheca) m a y be s i g n i f i c a n t . I n t h e Stoibostrombus crenulatus (exc1uding the elon Wangkonda Lst. a sheUy fauna, including gate morph restricted to the upper levels of the Halkieria sp., occurs at a substantially lower horizon than the first appearance of Dailyatia. Mt. Scott Ra. section) and 'Hyolithes' con ularioides in the Curramulka, Horse Gully, and International correlations Mt. Scott Ra. sections (Figs 3,4,6). Beneath the A. huoi Zone there are few secure indicators, but first appearance of Dailyatia and Trilobites. The Abadiella huoi Zone correlates transition from underlying dolomites to lime with the Parabadiella (=Abadiella) Zone of stones may provide some guide. 'Pre-Abadiella' China (Zhang,1985) and the P. tatei Zone faunas are dominated by Dailyatia, Micrina (and probably equates to the succeeding Eoredlichia other tommotiids in Horse Gully such as Ec Zone of China (Zhang, 1985); this is based on centrotheca guano and Kulparina rostrata) and occurrence of Eoredlichia shensiensis in the P. Thambetolepis. Appearances of these taxa may tater Zone and in the Chiulaotung Formation be staggered, but the problems of sampling from (Chiungchussu Stage) of southern Shaanxi and these dolomites means' that the order of ap P. tatei [=P. carinata (Zhang & Zhu in Zhang pearance is provisional. W.T. et ai., 1980)] in the latest Chiungchussu to The local range of Dailyatia macroptera and . earliest Tsanglangpu age Jiumenchong Forma Micrina etheridgei seems to be variable, with tion of Guizhou Province. Correlation of the P. these taxa persisting at Curramulka. Pojetaia tatei Zone with the USSR is through Prouktaspis .
EARLY CAMBRIAN FOSSILS, S. AUST.
MOODLATANA FMN
89
WIRREALPA LST
88
17
•
BILLY
ORAPARINNA SHALE
1499
FA?. V
�
1592,S7 � 1595 1596 ·
�
1588 1589 1590.1599
X cs::
from Emu Bay Shale, Kangaroo Island
PARARAIA JANEAE ZONE
FA9, 11, 12
1 � PARARA LST 1585 1584 1580,83 1509,1498 1503 1594
FM,7
FA3, 5,6
WOODENDINA DOLOMITE
t
PARACHILNA FMN
SUBGROUP (
Fig. 8. Cumulative range chart for trilobite faunas shown on Fig.7. All locality numbers shown against the column refer to NMVPL localities given in the Appendix. The simplified schematic litho logical column forthe whole area is provided by Dr DJ. Gravestock, South Australian Department of Mines and Energy and reflects the most recent knowledge of rock relationships. Thicknesses are not to scale as the basinal formations on the right of the column are far thicker than the platformal ones on the left. A substantial part of the section of the Billy Creek Formation is ommittedbecause it is unfossiliferous. The zonation proposed on trilobites is indicated and its relationship to the Faunal Assemblages scheme of Daily (1956) is inferred. The Fauna! Assemblage scheme of Gravestock (1984) based on archaeocyathids is also shown using the original notation of Roman numerals.
in the latest Atdabanian of Siberia (Repina in Khomentovsky & Repina, 1965), in the lat est A t d a b a n i an o f Mo ng o l i a (Korobov,1980) and in the late Atdabanian of Tuva (Pokrovskaya in Zhuravleva 1967). With these genera as-
Egyngolia
Pararaia (=Tannuolaspis)
et al.,
P. tatei
sociated in the Zone the immediately older A. Zone must also be considered to correlate with an earlier horizon in the Atdaba man. Correlation of these two oldest Australian trilobite zones with other parts of the world is
huoi
18
STEFAN BENGTSON
et
al.
more difficult. In Morocco Abadiella occurs in the Timghitien Stage (Ill of Hupe, 1953) which may correlate with the A. huoi Zone of South Australia, but this is speculative. In Spain Alanisia guillermoi occurs in the upper Marian iense Stage (Sdzuy,1971), above Serrodiscu5. Its Australian associates in the A. huoi zone would tend to suggest a more likely correlation with the o l d e r dolerolenoid f a u n a of t h e Spanish Ovetiense Stage. Occurrence of this species in Spain remains anomalous. No avenues exist for c orrelation of t hese two oldest Australian trilobite zones with North America. No means of correlating the P. bunyerooensis Zone to any other part of the world exists at present. The faunule from NMVPL1499 is assigned to the P. janeae Zone on lithological grounds (DJ. Gravestock, pers. comm.) which fits with the range of Micmaccopsis throughout the Botomian in Siberia (Repina in Khomentovsky & Repina, 1965), and the early Tsanglangpu age of Red lichia endoi in China (Lu,1950). The P. janeae Zone fauna is not easily corre lated but the association of Paleofossus, Serro discus, Atops (being described elsewhere by J.B. Jago & P. A. Jel1), and Kootenia suggests the Botomian Stage of the Siberian scheme and in particular the late Botomian based on the first three genera. Moreover, Bergeronielius a n d Bergeroniaspis, w h i c h a re s o c o m m o n throughout the Botomian in USSR, are ex tremely similar to Hsuaspis from South Australia (pocock,1964). Korobovia gen. novo of the P. janeae Zone may be present in Mongolia during the late Atdabanian and Lenian and in Gorny Altay during the Botomian and Lenian. In China Redlichia takooensis, Hsuaspis, and Hebedis cina (=Szechuanaspis) allow correlation with the Tsanglangpu Stage and probably the early part of that stage according to published accounts, although range charts for the Early Cambrian of China are not yet available. Kootenia diutina occurs in the Nevadella Zone of North America (Fritz,1972) and Serrodiscus is characteristic of that zone also, but no closer correlation is possible. Serrodiscus is the only point of similarity with Europe, occurring in the Callavia Zone (Hupe,1953; Sdzuy,1961), but this could hardly be considered a satisfactory correlation. The highest trilobite occurrences in South A u s t r a l i a o f Redlichia guizhouensis, t h a t resembles R. chinensis in many respects, and Onaraspis may correlate with the Lungwang miao Stage of China and most probably with the R. chinensis Zone. Similar correlation is sug gested for other parts of Australia also.
Molluscs. Stratigraphic ranges of most Early and Middle Cambrian molluscs are not yet well.es tablished, but some general patterns are begin ning to emerge. The most distinctive and widespread molluscs of the oldest Cambrian faunas are probably the monoplacophoran Latouchella korobkovi (Vostokova,1962), the gastropod Aldanella attleborensis (Shaler & Foerste,1888), and the rostroconch Watsonella crosbyi Grabau,1900 (=Heraultipegma varen salense (Pojeta & Runnegar,1976; see Landing, 1989); Rozanov e t al.,1969; Bengtson & Fletcher, 1983; Landing, 1988,1989). Aldanella and L. korobkovi are unknown from Australia but Watsonella has been recorded (as Heraultia Cobbold) from the Mount Terrible Formation on the Fleurieu Peninsula (Daily et al., 1976). In China, both Aldanella and Watsonella occur in the younger Meishucunian faunas of Hubei (Ping, 1984; Yu,1987). Co-occurrence of Anabarella drepanoida, Yochelcionella chinensis, Pelagiella adunca, and Pojetaia runnegari with Hsuaspis in the Xinji Formation of the North China Platform in Henan (He et al.,1984; Pei,1985; He & Pei,1985; Chen & Wang,1985) provides a good but ap proximate correlation between the Pararaia janeae Zone and the later part of the Tsanglangpu Stage in China. Pelagiella adunca is also found w i th Actinotheca and protolenids including Hsuaspis in the Yutai shan Formation, Anhui (Xiao & Zhou, 1984a,b). Small s ke letal fossils. The Precambrian Cambrian boundary sections in A ustralia (Daily,1956,1972, 1976) contain well-preserved Ediacaran assemblages a stratigraphically short interval (Mount,1988) below Cambrian rocks. These latter include clastics, with a diversity of trace fossils and carbonates with abundant ar chaeocyathids, small skeletal fossils and trilobites. The Australian sections have not been c o n s i d e r e d a s c a n d i d a t e s f o r b ou n d a r y stratotypes because of a, low diversity and poor preservation of the earliest skeletal assemblages, b, until recently (Crimes,1987; Narbonne et al., 1987) a reluctance to use trace fossils for biostratigraphy, c, unconformities close to the boundary (Mount,1989), and d, lack of detailed information on the Cambrian biotas. Brasier (1986a, 1989) attempted to establish a working biostratigraphy on small skeletal fossils by emphasizing first appearances, key taxa, and a sequence of biological and oceanographic events. Such schemes provide a framework for discussion, but agreement on detailed correla tions is still elusive. Correla tion between Siberia and Australia was reviewed by Daily (1972, 1976) and Rozanov & Sokolov (1984), and
EARLY CAMBRIAN FOSSILS, S. AUST.
broadly we would agree that sequences inves tigated here correlate with the Atdabanian, citing evidence fr om archae ocyathids (G r ave s tock,1984), small skeletal fossils, and trilobites. Our investigation of small skeletal fossils from essentially the same section in the Mt. Scott Ra. shed no light on the conclusions of Gravestock (1984) who correlated his Assemblages I and II with the Atdabanian Bazaikha and Kameshky horizons of the Altay-Sayan. Gravestock (1984) noted that correlations be tween Altay-Sayan and the Siberian platform were not entirely secure, but within the USSR it is to this region and Kazakhstan that one must turn to pursue similarities based on small skeletal fossils. Those regarded as significant include the co-occurrences of cambroclaves which appear in the upper part of our sections (Figs 3-6) and define the lower half of the Rhombocorniculum cancellatum Zone in Kazakhstan, a division regarded as equivalent to the upper Atdabanian (Missarzhevsky & Mambetov,1981). Similarly, although Microdictyon ranges into the Middle Cambrian (Bengtson et al., 1986), its first occur rences in Kaz akhstan, and by inference Australia, are upper Atdabanian.· Other com parisons are indicative rather than conclusive. They include the occurrence of Lapworthella cf. fasciculata, which has some similarity to the Atdabanian L. luc ida from Siberia (Mesh kova,1969) and northwest· Canada (Conway Morris & Fritz, 1984), and Microcornus, typical of Atdabanian assemblages in Kazakhstan (Mambetov,1972), Great Britain (Matthews & Missarzhevsky, 1975; Hinz,1987), and China (Duan, 1984). Some similarities exist between the Lower Cambrian faunas of Australia and China. How ever, the faunal resemblances are less striking than might be predicted from the pala eo geographic proximity postulated on palaeomag netic data (Lin et al., 1985), and the strong endemicity of the second of three Chinese small skeletal fossil zones (Qian & Bengtson, 1989) is notew orthy. Disagreement on correlation of these three zones with other sections is being replaced by a consensus that they are respective lyequivalent to the Nemakit-Daldyn (Manykay), Tommotian and upper Atdabanian-Botomian. Australian small skeletal fossils investigated show some similarity to the third Chinese zone. Particul'arly significant is the co-occurrence of Actinotheca and cambroclaves (Duan,1984), but other similarities are m· Beyond the USSR and China documentation· of small skeletal fossils is at a preliminary stage. Eccentrotheca kanesia in the Callavia Zone of Avalonia (far eastern North America) indicates an upper Atdabanian age (Landing et al., 1980;
19
Landing,1988), and although the Australian record is specifically distinct its similarity is consistent with the proposed age. Brasier (1986a,b) proposed a lineage of four species ·of Sunnaginia spanning the Tommotian and At dabanian. Unfortunately our material is relative ly poorly preserved and cannot be easily placed in Brasier's (1986a,b) scheme. However, their occurrence in the Sellick Hill Formation and Fork Tree Lst. is probably lower Atdabanian or upper Tommotian. Archaeocyaths from the same formation, however, suggest an Atdabanian to possibly early Botomian age (Debrenne & Gravestock, 1990). Evidence for inter-continental correlations, therefore, is not definitive, but small skeletal fossils broadly support Gravestock's (1984) con tention that the Ajax Lst. and its correlatives span much of the Atdabanian, and implies that the Wangkonda Lst. and Mount Terribh; Formation of the Fleurieu Peninsula are Tommotian. It is also worth emphasizing that even given uncertainties of precise correlations between Australia and elsewhere, notable extensions in vertical ranges include Anabarites and Proto", hertzina, both of which have been taken to be indicative of the earliest assemblage of small skeletal fossils (e.g., Missarzhevsky,1982). While this may be true for some regions and at a specific level, it emphasizes that a depauperate fauna of Anabarites and Protohertzina cannot be assumed to be of earliest Cambrian age in the . absence of independent data.
Systematic palaeontology Repositories for the material described herein are indicated by the following prefixes:- Adelaide University Geology Department, Adelaide (AUGD), Australian Museum, Sydney (AM), British Museum, London (BM), Geological Sur vey of Canada, Ottawa (GSC), �useum of Vic toria, Melbourne (NMVP), N anjing Institute of Geology and Palaeontology, Nanjing (NIGP), Queensland Museum (QM), South Australian Museum, Adelaide (SAMP), Swedish Museum of Natural History, Stockholm (SMNH), Univer sity of New England, Armidale (UNE), and United States National Museum of Natural His tory, Washington, D.C. (USNM). Locality registers of the Museum of Victoria and Univer sity of New England are indicated by the prefixes NMVPL and UNEL, respectively, and measured rock sections (RS) refer to localities within sec tions measured by BJC. Full details of all measured sections aTe given in the APPENDIX.
20
STEFAN BENGTSON et al.
CYANOBACTERIA [BNR] F il a mentous cyanoba cteria are commonly preserved in three main ways in Early Cambrian carbonate rocks. In forms such as Girvanella and Obruchevella, the sheaths secreted by the or ganisms were mineralized duringJife; these cal cified sheaths are visible at high magnification in some thin sections. In other cases, the calcified sheaths are coated or filled with fine-grained apatite. Other endolithic cyanobacteria inhabited the walls of various kinds of carbonate shells and sclerites. These are visible in thin sections but are best observed as phosphate fillings on the phos phatic internal moulds of shells and sclerites. Division CYANOPHYTA Smith,1938 Family POROSTROMATA Pia,1927 Girvanella Nicholson & Etheridge,1878 Type species. Girvanella problematica Nichol son & Etheridge,1878, Late Ordovician, Scot land. The genus has a stratigraphic range of latest Proterozoic-middle Cretaceous (Danielli, 1981-, Chuvashov & Riding, 1984). Diagnosis. Microscopic tubular encrustations andlor impregnations of sheaths of fHam'entous organisms; filaments arranged at random or prostrate, rarely vertica11y; filaments single or in growths of variable size, shape and density' orientation parallel to random; filaments un� branched and slightly to highly sinuous; cell space approximately circular in cross-section, sometimes compressed or with slight irregular ities (Danielli,1981, p. 96). Girvanella sp. (Fig. 9D, L-N) Material. Uncounted number of specimens in microfossil residues and one richly fossilifcrous thin section.
Distribution. Unknown. Described specimens are from UNEL1847, Parara Lst., Curramulka. Description. Irregularly packed, unbranched, untapered, calcareous sheaths about 7-10 �m in diameter. Sheaths are circular in cross-section and may be coated with a thin layer of finely crystal1ine apatite (Fig. 9D). Remarks. Calcified sheaths of topotypes of the type species of Girvanella are about twice the diameter of the species described here (Wood, 1957), but other narrow forms are known from the Early Cambrian (Danielli, 1981) and some of these have been referred to G. problematica (Ed horn, 1979). The morphology and taxono my of Girvanella was thoroughly reviewed by Mamet & Roux (1975) and Danielli (1981). Family OSCILLATORIACEAE Gomont,1892 Obruchevella Reitlinger,1948 Type species. Obruchevella delicata Reitlinger, 1948, from the Early Cambrian of Yakutia, U .S.S.R. Other described species of Obruche vella range in age from latest Proterozoic to at least Middle Cambrian. Diagnosis. Spring-shaped, h elical1y-c oiled, tubular sheaths which may have been mineral ized or unmineralized during life; sheaths cir cular in cross-section and up to c. 30 /-Lm in diameter; helices also circular in cross-section and up to c. 150 �m in diameter. Remarks. Obruchevella is usually considered to have been an oscillatoriacean similar to the Recent Spirulina (Peel,1988). Other living spi ral-shaped cyanobacteria include the strain of Anabena in Fig. 80C. It may therefore be unwise to place too much emphasis on the similarity to Spirulina, given the geological age of Obru chevella.
Fig. 9. Cyano�acteria. A,B,E,H-K, Obruchevella delicata Reitlinger, 1948, Parara Lst., Curramulka . A,B,E, . phosphate fillIng of sheath wrapp�d ar�und phosp � atic external mould of part of sheath, SAMP29048, l!NEL1847, x500, x750, x900. F, thlO section of calcifIed sheath cut perpendicular to coil axis, plane-polarized lIght, UNER50601, UNEL1847, x400. G, phosphate filling and coat of calcified sheath now dissolved SAMP29050, U �EL18�7, x22�O. H, thin �ection cut parallel to coil axis showing finely cr;stalline calcified sheath enc1�sed 10. and fdled with phosphatJc matrix (black), cross-polar ized light, UNER50601, UNEL1847, x400. I,J, t � 1O S�C!lOn cut parallel to coil ax �s showing finely crystalline calcified sheath in carbonate matrix and sparry calclte f !lhngs ,arrow), �lane-'polartzed and cross-polarized light, UNER50601, UNEL1847, x400. K, phosphate r�phca of tIghtly cOl]�d fIlament, SAMP29051, UNEL1846, x290. C, Anabena sp., living spiral cyanobacterlUm for companson wlth Obruchevella, South Australian isolate, courtesy ofM.T.C. Runnegar, x300. . D, L-N, Gtrvanella sp., UNEL1847, Parara Lst., Curramulka. D,L,N, phosphate coats or replacements of calcareous sheaths, SAMP29049, x900, x300, x270. M, calcified filaments in thin section of Iim"estone' plane-polarized light, UNER50601, x 1 00.
EA!U-Y CAMBIIIAJ< fDS'.lU>, S \VSJ . .
.
21
EARLY CAMBRIAN FOSSILS, S. AUST.
Obruchevella delicata Reitlinger, 1948 (Fig. 9A,B,E,H-K) Material. Uncounted number of specimens in microfossil residues and one richly fossiliferous thin section. Distribution. Unknown. Described specimens are from UNEL1847, Parara Lst., Curramulka. Description. Specimens are calcified (Fig. 9H1) or preserved as phosphatic coats and fillings (Fig. 9G). Even spiral fillings of the helix axis may be identifiable. The helical coils are regular or irregular, about 40-50f.Lm in internal diameter and 80-100f.Lm in external diameter. The space occupied by the trichome was c.10j-Lm in dia meter and the calcified sheath about 5j-Lm thick. One exceptional specimen (Fig. 9H) has the sheath carbonate enveloped in fine-grained phosphate. The small size of the calcite crystals in the sheath (c. 1f.Lm) strongly suggests that the carbonate of the sheath is primary. By contrast, the spaces left by the trichomes are commonly filled with larger crystals of a sparry calcite ce ment (Fig. 91,J). Remarks. Peel (1988) reviewed the morphology and taxonomy of Obruchevella and the related Spirellus Jiang and Jiangispirellus Peel. Ac cording to Carol Mankiewicz (per. comm. 1988), the described species of Obruchevella inter grade in size. Those described here lie within the range referred previously to O. delicata. Family unknown Endoconchia Runnegar, gen. nov.
Etymology. Greek, endon, within and Latin, concha, mollusc shell. Type species. Endoconchia lata sp. nov., from UNEL1761, base ofParara Lst., Horse Gully. Diagnosis. Tubular, unbranched, microscopic tunnels that run parallel to the surface of srn all , thin carbonate shells and sclerites; believed to have been formed by endolithic Cyanobacteria.
23
Distribution. Endolithic borings of this type are found in microfossiliferous Ear] y Cambrian limestones from Siberia, France, China and Australia. They occur most commonly in mol lusc shdls (Runnegar,1985a) but are also known in chancelloriid sclerites and Anabarites. The oldest examples are from the Tommotian of Siberia (Fig. lOA, D) and the Meishucunian of Hubei, China (BNR, unpubl. obs.) . They demonstrate that microbial endoliths, probably unicellular or filamentous cyanobacteria, in vaded skeletal carbonates almost as soon as mineralized skeletons evolved. The palaeoen vironmental significance of these widespread Cambrian endoliths is, as yet, not well known... Remarks. Although endolithic microborings have been d escri bed a nd illustrated from Recent, subfossil and fossil carbonate substrates. (e.g., Golubic et al., 1975), most have been iden tified with extant taxa of algae or fungi, and few· have been given separate scientific names. This practice has inhibited the communication of in formation about fossil microbial endoliths, and is eschewed in some recent works (e.g., Vogel et aI., 1987; Green et al., 1988). None of the pre viously named. endolithic structures closely resembles Endoconchia. Endoconchia lata Runnegar, sp. nov. (Fig. lOA,D?, B,C,F-,-H)· Etymology. Latin, latus, wide or broad.
_
Holotype. AMF61802, UNEL 1761,-base of Parara Lst., Horse Gully. Diagnosis. Mean tunnel diameter c. lOj-Lm. Description. Long, unbranched tunnels cut parallel to the surface of the host substrate; best preserved as phosphatic fillings attached to an internal mould (Fig.lOF,G). The borings have a constant diameter of c. lOJJ,m in both prismatic and fibrous substrates. Tunnel ends are either rounded or slightly bulbous. Remarks. Endoconchia lata differs from E. an-
Fig. 10. Endoliths. A,D, Endoconchia sp., SAMP29005, phosphate filling of boring attached to phosphate internal mould of Aldanella rozanovi Missarzhevsky, basal bed of Pestrotsvetnaya Suite, Dvortsy, AJdan, Yakutia, x400, x60. B,C, Endoconchia lata Runnegar, sp. nov., 10j.Lm wide casts of borings on internal mould of Pararaconus staitorum Runnegar, sp. nov., SAMP29012, UNEL1761, x600, x900. E, Endoconchia angusta Runnegar, sp. nov., end of 3j.Lm wide boring with terminal and subterminal swellings cast in phosphate and attached to internal mould of Yuwenia bentleyi Runnegar,1981, AMF61802, UNEL1761, x600. F,G, En
doconchia lata Runnegar, sp. nov., phosphate cast of unbranched boring extending from near aperture of shel1 of Bestashella tortilis Missarzhevsky, 1981, SAMP29001, UNEL1761, x350, x80. H, ho)otypes of Endoconchia lata Runnegar, sp. novo and Endoconchia angusta Runnegar, sp. novo attached to intenal mould of Yuwenia bentleyi Runnegar,1981, AMF61802, UNEL1761, x300.
24
STEPAN BENGTSON et al.
gusta sp. nov. in tunnel diameter and in lacking well-developed spheroidal expansions (Fig. 10E). Both species are found within a single shell (Fig.10H).
Endoconchia angusta Runnegar, sp.nov. (Fig. lOE,H) Etymology. Latin angustus, narrow. Holotype. AMF61802 from UNEL1761, base of Parara Lst., Horse Gully. Diagnosis. Mean tunnel diameter c. 3f,.Lm. Description. Long, unbranched tunnels cut parallel to the surface of the host substrate; best preserved as phosphatic fillings attached to an internal mould (Fig. 10H). The borings have a constant diameter of about 3 f,.Lm. Tunnel ends and some other points of the tunnel may be expanded into 5 f..Lm-diameter bulbous chambers (Fig.10E).
SPICULES [SB] Spicules, isolated biomineralized elements usually formed within living tissue', overlooked in fossil assemblages. They are taxonomically recondite and are often poorly preserved because of their size, sometimes also because of their composition. Nevertheless, spicules are very widespread among modern metazoans (e.g., Rieger & Sterrer, 1975). Inten sified studies of fossil spicules can only enhance understanding of metazoan diversity. The Australian samples investigated here con tain a wide diversity of spicules and sclerites. (The two categories are not mutua11y exclusive. Spicules are one type of sclerites, but the former term is usually reserved for small, isolated ele ments with a shape often approaching that of inorganic crystals and usually fonned within living tissue rather than as extra-epithelial mineralizations. 'Sclerite' typically refers to somewhat larger elements of a composite exos keleton.) The mineralogical composition varies from opal (preserved as quartz) to aragonite and calcite (preserved as calcite or replaced by phos phate). Major taxa represented are Porifera ( H ex a ct inellida, C a l c ar e a , a n d probable Demospongea, plus a number of sponge-type spicules not identified to class) and problematic spicules that may represent extinct groups (Radiocyatha and others) or belong to extant phyla (possible octocoral and tunicate spicules, etc.).
Remarks on Early Cambrian sponges
Finks (1970, 1983) and Rigby (1983,1986) reviewed knowledge on the early history of the Porifera. No body fossils of sponges were found in the present study, but our spicular assemblages augment knowledge of the earliest poriferans. In general, the Australian assemblages suggest a higher diversity and complexity of Early Cambrian sponges than previously recognized. Cambrian calcareous sponges mainly belong to the Order Heteractinida Hinde, 1888, now taken to exclude the Chancelloriidae, which are most probably not sponges (Bengtson & Mis sarzhevsky, 1981; Rigby, 1983, 1986). Heterac tinellid spicules are generally polyactinal, main ly o c t a ct i n e s . The triradiate spicules of Dodecaactinella cynodontota sp. novo may rep resent non-heteractinids. The discovery in Australian rocks of such spicules preserved in original calcite provides solid evidence for an early appearance of the type of biomineraliza tion characteristic of Class Calcarea. In modern Calcarea, spicules are formed by sclerocytes, generally two per ray (Jones, 1970). The spicules consist of concentric layers of organic matter and high-Mg calcite in crystallographic continuity; each spicule behaves optically as a single crystal. Spicules of Dodecaactinella conform in this respect, while their triradiate morphology also supports an affinity to the Calcarea (cf. Mostler, 1985). The presence in the Australian sections of typi cal hexactinellid spicules with siliceous com p o s i t i on and axial c anal confirms Early Cambrian hexactinellids of modern type. Finks (1970, 1983) regarded the most primitive hexac tinellids to be the Protospongia type, with thin body walls supported by a single layer of dermal stauracts (spiculcs with only four rays, all in one plane). The Austr�lian �picules include a . , majority of three-dImenSIonal splculcs WIth well-developed rhabds (shafts), suggesting a thicker wall than that of Protospongia. Which type of hexactinellid architecture is more primi tive s e e ms unanswer a b l e by r ecourse to stratigraphic occurrence. Other siliceous sponges of possible demo sponge affinity (Taraxaculum, Nabaviella) also had well-developed rhabds. Such spicules also occur in the eiffeliid heteractinids. The majority of sponge-like spicules in th� Australian se� tions, however, cannot readIly be placed 10 known sponges. Some of these are of heteracti nid type, but their preservation suggests that originally they had a different composition. Al though we have not been able to elucidate the nature of all of these spicules, it seems that the
EARLY CAMBRIAN FOSSILS, S. AUST.
25
Fig. 11. Dodecaactinella cynodontota Bengtson & Runnegar, sp. novo All x 125, except D and E. A and B stereo-pairs. A, SAMP30201, Mt Scot! Ra., Ajax Lst., UNEL1866. B-E, holotype, SAMP30202, from same section as A, UNEL1872. D, detail of C, x 1000. E, detail of B, x 1000.
26
STEFAN BENGTSON et al.
12. Eiffelia araniformis (Missarzhevsky, 1981). All xl00, except B. A and D stereo-pairs. A-C, SAMP30203, Kulpara Lst., 6529RS104. B, detail of A, x500. D,E, SAMP30204, same sample as A-C. F,G, SAMP30205, Kulpara Lst, Horse Gully, 6429RSI05. H,!, SAMP 30206. Same sample as F;G.
Fig.
EARLY CAMBRIAN FOSSILS, S. AUST.
27
Australian material may provide a basis for a better understanding of the 'heteractinids'.
D,escription. Triacts, with the main rays diverg ing at 120°, initially in one plane. The rays branch dichotomously (Fig. 11F) or trichotomously Phylum PORIFERA Grant, 1872 (Fig. lIB), c. 5�100f.1m from the center. The Oass CALCAREA Bowerbank, 1864 lateral branches diverge at c. 80°, usually curving Family unknown [SB,BNR] slightly towards each other and remaining ap proximately in the main plane of the spicule(Le. Dodecaactinella Reif, 1968 the initial branching plane of the main rays). The central branch (when present) is straight and 1968 Dodecaactinella Reif, p. 741. projects upwards from the spicule plane (Fig. 1985 Polyactinella Mostler, p. 15. lIA,C). A few specimens(Fig. 11A) have three 1985 Sardospongia Mostler, p. 16. accessory rays between the main ones, diverging 1987 Demospongia Fonna 2,4; Shabanov et al., p. from the spicule center at 60° to the main rays. 129. The holotype represents the most common spic ule type; the other two(Fig. l1A, F) being rare. The spicules consist of calcite (confirmed by Type species. Dodecaactinella oncera Reif, X-ray diffraction).. Specimens from etching 1968. residues are strongly. corroded, on account· of Other species. D. cynodontota Bengtson & Run dissolution faces of the crystal lattice (Fig. negar, sp. nov.; D. furcata (Mostler, 1985); D. 11D,E). Their consistent orientation over the triradiata (Mostler, 1985). whole spicule suggests that it consists of· one calcite crystal. This· is confirmed by observaDistribu tion. Lower Cambrian (Atdabanian of . tions in thin sections, which show the �alcite «;; axis to be directed normal to the· plane of the Siberia and Australia; Lower-Middle C ambrian of Sardinia; Upper Ordovician of Estonia. spicule(Le. a direction perpendicular to the page . . in Fig. 11A,B,E,F). Diagnosis. Spicules triradially symmetrical, Remarks. A l t h o u g h R e i f· (1968) r efe r r e d with the three main rays having bi':' or trifurcat ing ends.Three accessory rays sometimes radiate Dodecaactinella to the hexactineUids, Rigby & from center. Toomey (1978) and Mostler (1985) suggested that it was a calcareous sponge. Our findings support the latter view, and the specimens il Taxonomic comparisons. T h e A us t r a l i a n samples have dodecaactines co-occuring with lustrated by Mostler (1985) and Shabanov et al. forms similar to those used by Mostler(1985) to (1987, p1.34, fig. 3) show similar c alcite cor rosion surfaces as the Australian ones. -. erect Polyactinella and Sardospongia. This sug gests that Mostler's genera are synonymous with Dodecaactinella. Order HETERACTIN ID A Hinde, 1888 [SB] Family EIFFELIIDAE Rigby, 1986 Dodecaactinella cynodontota Bengtson & EitTelia Walcott, 1920 Runnegar, sp. novo (Fig. 11) Etymology. Greek kynos, dog, odontotos, with teeth; alluding to the similarity of the etched spicular calcite to dog-tooth spar. Ma terial. Holotype, SAMP30202 (Fig. 11 B-E), fromUNEL1872, Mt. Scott Ra., Ajax Lst.; c. 20 paratypes. Distribution. H o r s e G u l l y , Ku l p a r a Ls t. ( U NELI857) ; C u r r a m u lk a , P a r a r a Ls t . (UNELI845, 1847-1849); Wilkawillina Gorge, Parara Lst.,(NMVPLI594); Mt. Scott Ra., Ajax Lst. (UNELI866,1872). Diagnosis. Spicules varying, including three rayed ones with bifurcating or trifurcating ends, aswell as forms with accessory rays between the mam ones.
1920 1981
Eiffelia Walcott, p. 323. Lenastella Missarzhevsky in Missarzhevsky & Mambetov, p. 75.
1984 1984
Actinoites Duan, p. 166. Niphadus Duan, p. 167.
D iagnosis. Spicules 6-rayed, with rays diverg ing at 60°, occasionally with a 7th, usually short, central ray perpendicular to or. inclined to the plane of the other six. Taxonomic c omparisons. See discussion o f Lenastella, Actinoites, andNiphadus below. EitTelia a ra niformis (Missarzhevsky, 1981) (Figs 12,13) 1981
Lenastella araniformis Missarzhevsky in Mis-
28
STEFAN BENGTSON et al.
Fig. 13. Eiffelia araniformis (Missarzhevsky, 1981). Curramulka, Parara Limestone. A,B, x75, C-G, xlOO. A and E stereo-pairs. A,B, SAMP30207, UNEL1848. C, SAMP30208, UNEL1846. D, SAMP30209, 8-rayed spicule tentatively assigned. Same sample as C. E,F, SAMP3021O. Same sample as C. G, SAMP30211. Same sample as C. sarzhevsky & Mambetov, p. 76, pI. 12, figs
1981
1,10. 1981
Lenastella aculeata Missarzhevsky in Missar
1984
Actinoites universalis Duan, p.167, pl.4, figs
1984
Actinoitesdiclinatus Duan, p.167, pl.4, figs
1984
Actinoites simplex Duan, p. 167, pl.4, fig.6.
5,12.
zhevsky & Mambetov, p. 76, p1.12, figs 2-4. 1981
Lenastella mucronata Missarzhevsky in Mis sarzhevsky & Mambetov, p.77, p1.12, figs 8,9,11.
Lenastella umbonata Missarzhevsky in Mis sarzhevsky & Mambetov, p.77, p1.12, fig.12.
11,13-14.
EARLY CAMBRIAN FOSSILS, S. AUST.
1984 1984 1986
29
in the same sample (UNE L1857, which is rich fig.17. in phosphatized Eiffelia s p i c u l e s ) are n o t Niphadus complanatus Duan, p.168, pI.4, fig.8. preserved in this manner (see above). Lenastella sp. Laurie,p.447, fig.IOC. Niphadus xihaopingensis Duan, p.168, pI.4,
Material. About 1000 specimens. Distribution. Upper Atdabanian of Maly Kara tau (type occurrence in the.Zhanaaryk Member of the Shabakty Formation, Aktugay), Talasskiy Alatau, Siberian Platform, Mongolia, Europe and Australia ( f ide M am b e t o v & M i s s arzhevsky,1981); Xihaoping Formation, Shennongjia Co., Hubei, China (Duan, 1984); Horse Gully, Kulpara Lst. (6429RS103-106, UNE L1857); Horse Gully, Parara Lst. (6429RSl07111, UNEL1852-l854, 1856); Curramulka, Parara Lst. (UNEL1845-1849, 1851); Kulpara, Parara Lst. (6529RS104--106); Mt. Scott Ra., Ajax Lst. (UNEL1866, UNEL1869-1874). .
)
Diagnosis. Member of Eiffelia with six rayed spicules and less common seven rayed forms with central ray usually short and sometimes inclined relative to the plane of the six rays. Body shape and spicule arrangement unknown. Description. Spicules have a regular six-rayed disk, 0.25-1mm in diameter, with rays consist ently diverging at 60°. Occasional specimens may be irregular (Fig. 12H). The rays are slender and usually of equal length, but may be of une qual length (Fig. 12A). They usually make a slight angle to the plane of the central disk, so that there obtains a concave (Fig. 12A) and a convex (Fig. 12D) side. A smaller number of spicules have a seventh ray emanating from the convex side of the disk. This ray may be short and is then often inclined at a mbre or less sharp angle (Fig. 13A,B,E,F). It may also be developed as a rhabd, perpendicular to the disk ( F i g . 1 3 C , D , G ) . O c c a s i o n a l specimens have a sixth ray on the opposite side of the spicule (Fig. 13D); their inclusion inE. araniformis is tentative. The central part of the convex side in some specimens has more or less regular nodes, about lOf,1m in diameter (Fig. 12A). The spicules are otherwise smooth, with a finely granular pattern on the scale of about 1 f,1m sometimes visible (Fig. 12B). Spicules are preserved in the etching residues due to coating or surficial impregnation with phosphate. In spite of their abundance they have not been identified in thin sections. They were probably calcareous, judging from similarity in preservation with known calcareous fossils in the same rocks. It should be noted, however, that the calcitic spicules of Dodecaactinella cynodontota
Taxonomic comparisons. Spicule types figured by Missarzhevsky &. Mambetov (1981) from Maly Karatau and by Duan (1984) from Hubei under a number of generic and specific names (see synonymy list), all appear in the Australian assemblage. Australian forms with six radiating rays (Fig. 12) correspond to L. araniformis, L. mucronata, N. xihaopingensis, and "N. compla natus; the ones with a short, oblique central ray (Fig. 13A,B,E,F) to L. aculeata andA.· diclina tus; and the ones with a perpendiculax <;�ntral ray (Fig. 13C,G) to L. umbonata, A. universalis,.and (probably) A. simplex. Forms with two opposed central rays (Fig. 13D) are not represented in Missarzhevsky & Mambetov's or Duan's illustrations. " Consistent co-occurrences of the various spicule types in approximately coeval deposits in Kazakhstan, China, and Australia .a re good evidence that the different spicules belong to the skeleton of one species. Neither Missatzhevsky & Mambetov (1981) nor Duan (1984) made comparisons with Eiffe lia. Unquestionably, however, Lower Cambrian hexaradiate spicules belong to eiffeliids. ReJn vestigation (Rigby, 1986) of the type species -of Eiffelia from the. Burgess Shale,E. globosa, showed that, contrary to earlier statements, spicules are solid and unsutured. Rigby (1986) found no evidence of central rays in the spictiles, and concluded that" the body wan was thin, with a layer of at feast four size ranks of spicules. Although Middle Cambrian spicules of �. globosa with central rays are not known, the majority' of Lower Cambrian spicules similarly lack a central ray. It seems probable that Middle and _Lower Cambrian forms had similarly con structed spicular skeletons. The nodose central surface in E. araniformis (Fig. 12A,B) recalls some other heteractinids, such as the Carbonife rous Zangerlispongia (Rigby & Nitecki, 1975, pl.l, figs 2,3) and Tholiasterella (Rigby, 1983, fig. 12). ?Heteractinida indet. (Fig. 14) Other calcareous(?) spicules present in the Australian samples are reminiscent of other heteractinid types (cf. Rigby, 1983). Most dis tinct among these are forms with eight rays regularly diverging in one plane, with or without accessory rays in other planes. These may also be compared with r a diocyathan nesasters (Zhuravlev, 1986).
30
STEFAN BENGTSON
et
al.
Fig. 14. Spicules of ?Heteractinida indet. Kulpara Lst., Horse Gully, 6429RS105. All xlOO, except F. A, stereo-pair. A,B. SAMP30212. C,D, SAMP30213. E,F, SAMP30214. F, detail of E, x700. G,H, SAMP30215.
EARLY CAMBRIAN FOSSILS, S. AUST.
Class HEXACTINELLIDA Sollas, 1887 Order and family unknown Hexactinellid spicules in the samples are pen: tacts (Fig. 15A,B), which are most common, and stauracts (Fig. 15E) and hexacts (Fig. 15F). The rhabd, when present, usually has an acanthose surface (Fig. 15A,B,F). Broken rays show a dis tinct axial cavity (Fig. 15A,C,F). These spicules are essentially of 'modern' type, and it does not seem feasible to use their morphology to recognize particular taxa. Acan those pentacts and hex acts are known from several lo�alities in the Upper Cambrian (Howell & Van Houten, 1940; Rigby, 1975; Bengtson, 1986b), but very similar types also occur in modern hexactinellids. Class, order and family unassigned
Heterostella Fedorov in Shabanov et al., 1987 Type and only species. Heterostella eleganta Fedorov in Shabanov et al., 1987. Distribution. Lower· Cambrian (Upper Atdaba nian) of the Siberian Platform and Australia(?).
Heterostella? sp. A (Fig. 15G,H) Material. SAMP30221 from UNEL1873, Mt. Scott Ra., Aja x Lst. Description. This octactine spicule of apparent siliceous composition may derive from a spicu lar assemblage similar to that of H. eleganta (Shabanov et al., 1987, p1.35, figs 8-15; p1.36, figs 1-6), but in the absence of more complete material it can only tentatively be referred to Heterostella.
Nabaviella Mostler & Mosleh-Yazdi, 1976 Type species . Nabaviella elegans Mostler & Mosleh-Yazdi, 1976. Other species . N. triradiata Mostler & Mosleh Yazdi, 1976. Distribution. Iran, Upper Cambrian; Australia, Lower to Upper Cambrian. Kazakhstan, Lower Middle(?) Ordovician. Diagnosis. Siliceous spicules having one central ray that on one end carries 3-11 recurved lateral rays. The other end may carry an expanded knob or disc.
Nabaviella sp. A (Fig. 16)
31
Material. About 15 specimens from Mt. Scott Ra., Ajax Lst. (UNELI866-1868); Wilkawillina Gorge, Parara Lst. (NMVPL1594). Description. Spicules are in the shape of cla vules, i.e., having a central shaft pointed at one end and on the other end carrying prominent recurved lateral rays. Lateral rays number 3 (Fig. 16A,C,D), 4 (Fig. 16B,E,F,G) or 5 (Fig. 16H). The curvature is generally greatest about 1/3 to . 1/2 of the distance from the proximal to the distal end. The diameter of the disc formed by the lateral rays is 0.9-2.0mm. The rays are round,to oval in cross-section. The central ray is com pletely preserved only in one specimen (Fig. 16A), where it is 1.0mm long and tapers to a point at the distal end. The cross-section is round. No axial canal has been observed in any of the rays. Remarks. The available spicules are too few and too poorly preserved to serve as basis for a new species. They differ from the hemidisc-like spicules of N. elegans in having fewer ,lateral rays (3-5 vs. 6-11) and, judging from one specimen (Fig. 16A), in lacking a distal expan sion of the central ray. Moreover,lateral rays in N. elegans are often angular in cross-section and join to form a disc-like structure at their bases. From the same beds as yielded N. elegans Mostler & Mosleh-Yazdi (1976) described N. triraditita with three. short, strongly,· recurved, lateral rays. Only one specimen was figur�d and does not show the distal end of the central ray. Whereas our N. sp. A bridges the gap (in tenils of r a y numb er) between the t w o U p p e r Cambrian species, there is insufficient informa tion to judge whether or not N. triradiata is··a synonym of N. elegans, and where N. sp. A fits into the pattern. Nabaviella-like spicules also occur in the Lower Cam brian of the Siberian Platform (Shabanov et al., 1987, p1.36, fig. 13), the Upper Cambrian of Queensland (Bengtson, 1986b) and i n t h e L o w e r -M i d d l e (?) O rd o v i c ia n o f Kazakhstan ('Radiolaria? incertae sedis' of . Nazarov'& Popov, 1980, pl.17, figs 8,9). Discussion. Mostler & Mosleh-Yazdi (1976)in te rpreted Nabav iella as possibly related to Chan celloria, with a hollow spicule with dividing walls betw,een the rays (Mostler & Mosleh Yazdi, 1976, fig. 24). This s t r u c t u r e w a s s e e m i n g l y d edu c e d f r o m t h e t e n d e n c y o f t h e c e n t r al r a y to b e c o me de t a c h e d fr o m t h e d i s c f or m e d by t he b a s a l p a r t s o f t h e l a t e r a l ra y s . H o w e v e r , t h e in t er pr e t a tion w a s n o t c o n firme d in thin s e c t i o n . The Australian represe ntatives of
32
S TEFAN BENGTSON et al.
Fig. 15. A-F. Hexactinellid spicules. Ajax Lst., Mt Scat! Ra., UNEL1866. A, SAMP30216, x50. B,C, SAMP30217. B x50, C, detail of ray tip, x500. D, SAMP30218 , x50. E, SAMP30219, x50. F, SAMP30220, x30. G,H, Heterostella? sp. A, same section, UNEL1873, SAMP30221, xIOO. Nabaviella f igured here and by Bengtson (1986b) are siliceous and usually solid. They differ markedly in preservation from associated Chancelloria spicules (Figs 26,27), whereas the structure agrees with that found in siliceous sponges.
Mostler (19 86) presented the alternative proposal that the spicules known from Nabavi ella elegans are large hemidiscs h omologous to amphidisc microscleres of amph idiscophoran hexactinellids. This hypothesis is more in keep ing with spicule composition and structure, but
EARLY CAMBRIAN FOSSILS, S. AUST.
33
r
Fig. 16. Nabaviella sp. A. Mt. Scatt Ra., Ajax Lst., UNEL1866 (A,B) and UNEL1868 (C-H). All x50. A, stereo-pair, SAMP30222. B, SAMP30223. C,D, SAMP30984. E, SAMP30224. F, SAMP30225. G, SAMP30226. H, SAMP30227.
we see no way at present of testing it. The lack of a discernible axial structure in the Nabaviella spicules (Fig. 16) distinguishes them from those of associated undoubted hexactinellids, which have a distinct axial filament. Megasclere-sized clavules, hemi- or amphidiscs are known sporadically in the later Palaeozoic (Hall & Clarke,1899; Librovich, 1929; Kling & Reif, 1969; Mostler,1986). At least sometimes (e.g.,
Gryphodictya Hall & Clarke,1899) they occur in association with hexactinellid spicules. Taraxaculum Bengtson, gen. novo Etymology. Diminutive of Latin Taraxacum, dandelion; alluding to similarity of the spicules to flying seeds of dand elions. The name is neuter in gender.
34
STEFAN BENGTSON etal.
Fig. 17. Taraxaculum volans Bengtson, gen. et sp. novo Mt. Scot! Ra., Ajax Lst., UNEL1866. All x30 except C,L,N, and P. A,F,G, and N stereo-pairs. A-C, holotype, SAMP30228. C, x150, detail of A. D,E, SAMP30229.
F, SAMP30230. G,H, SAMP30231. 1,1, SAMP30232. K,L, SAMP30233; L, x600, detail, position indicated in K. M, SAMP30234. N. SAMP30235, distal end of broken shaft, x75. 0, SAMP30236. P, SAMP30237, distal end of broken shaft, x75. 0, SAMP30238. R,S, SAMP30239.
Type and only species. Taraxaculum volans, sp. novo
Etymology. Latin volans, flying; continuing the allusion to dandelion seeds.
D istribution. Australia, Lower Cambrian.
Material. Holotype SAMP30228 (Fig. 17A-C) from UNEL1866, Mt. Scott Ra., Ajax Lst.; about 100 para types.
Diagnosis. S iliceous spicules consisting of central shaft that at one end carries 4-7 ir regularly radiating lateral rays. Opposite end of central shaft pointed or split into two short processes. No axial canal or f ilament discernible.
Distribution. Mt. Scott Ra., Ajax Lst., UNEL 1 866-1868. Diagnosis. As f or the genus.
Taraxaculum volans Bengtson, sp. novo (Fig. 17)
Description. The s i liceous spicules have a
EARLY CAMBRIAN FOSSILS, S. AUST.
central shaft, O.5-1.2mm long arid about 70J.Lm thick, and carry at one end 4-7 lateral rays, up to O.6mm in length. The rays generally radiate out wards and slightly away from the plane perpen dicular to the central shaft. Occasional rays may protrude. in a markedly different plane (Fig. 17F). The arrangement of the lateral rays is ir regular; the rays may curve in different directions (Fig. 17G, M) and their angles of divergence within one spicule may vary considerably (Fig. 17B,E,H,J,S). Some radiate from the base of an adjacent lateral ray rather than from the axis of the central shaft (Fig. 17B, upper right niy). The opposite end of the central shaft is com monly split into two processes, diverging at about 30° (Fig. 17A,C,M,R). Single pointed tips (Fig. 17F,Q) and fragments showing a more elaborate branching of the two processes have also been found (Fig. 17N,P). No trace of an axial canal or filament is ob served in our material, neither in transmitted light nor on surfaces of broken rays (Fig. 17L). Remarks. Four-rayed specimens (Fig. 17D,E) may be confused with co-occurring hexactinel lid pentacts (Fig. 15A-C), but the lack of an axial canal or filament and the somewhat more ir regular shape of the rays are reliable characters for their identification. T he disposition of the slender lateral rays recalls that seen in spicules of Canistrumella alternata Rigby (1986, text-fig. 27) from the Middle Cambrian Burgess Shale, although the latter appear to lack central rays, except for proximal and distal 'buttons' at the ray junc tion. Rigby referred Canistrumella to the Eiffeliidae, thus implying an originally calcareous composi tion. With -the possible- exception of some iso lated calcareous spicules of Eiffelia, however, there is no direct evidence for the original com position of the Burgess Shale spicules (Rigby, 1986, p.5). The spicules of Canistrumella are preserved as limonite pseudomorphs after pyrite (Rigby, 1986, p.S9). 'Clawed· spicules . These siliceous spicules (Fig.18) co-occur withthe ones described above and show some attributes (slender, pointed, slightly irregularly disposed rays) suggesting that they may belong to Taraxaculum volans. This interpretation is speculative, but if future finds show their co-occurrence to be constant and if constructional or functional analyses pro vide independent evidence that they belong to the same scleritome, then 'clawed spicules' shoul d be included in T. volans. They are here described separately without being formally as signed t o taxon. The spicules are small, ray length up to 400 '
35
J-lm, with four, occasionally three (Fig. 18Q,R) lateral rays diverging at about equal angles slightly out of a plane perpendicular to the axis of symmetry. Each ray carries a short basal process that may be simple (Fig. 18E,N,P) or branching in antler-like fashion (Fig. 18C,J). No axial canal has been observed. Discussion. The type of siliceous spicule de scribed for T. volans, consisting of a central shaft (rhabdome) with lateral rays radiating from one end, is common among demosponges and hexac tinellids. The profound differences from the as sociated hexactipellids (Fig.1SA-F) noted above speak against an assignment of Taraxaculum to this group. Although the variability of demo sponge spicules seems sufficently great to ac;. commodate the Taraxaculum spicules (as well as the associated 'clawed spicules'), the known Cambrian representatives (Rigby,1986) do not offer a base for detailed comparison (but see comments on Canistrumella above). Althougff' there seem to be no reasons to doubt its affinity to the Porifera, the question of systematic affinity of Taraxaculum is left open. . Phylum, class, order, and family unassigned Microcoryne Bengtson, gen. nov.
Etymology. Greek mikros, small, and koryne, club, mace. The name is feminine in gender. _
Type and only species. Microcoryne cephalata sp. novo Distribution. Australia, Lower Cambrian. Diagnosis. Mace-shaped spicules, probably cal careous, 0.3-1mm long, with numerous short and blunt tubercles radiating to form an irregular head, and usually projecting further in one direc tion to form a stout shaft-like process. Microcoryne cephalata Bengtson, sp. nov. (Fig. 19)
Etymology. Greek kefaloto�, with a head. Material. Ho]otype SAMP30248 (Fig. 19A) from UNEL1874, Mt. Scott Ra., Ajax Lst.; c. 200 paratypes. Distribution. Horse Gully, Kulpara and Parara Lst. (6429RSI03-106); Mt. Scott Ra., Ajax Lst. . (UNEL1873-1874). Diagnosis. As for the genus.
36
STEFAN BENGTSON et al.
Fig. 18. 'Clawed spicules', possibly belonging to Taraxaculum volans Bengtson, gen. et sp. novo Mt. Scat! Ra., Ajax Lst., UNEL1866 (D-N, O,R) and UNEL1868 (A-C, O,P). All x75 except for C and J, x500. A,D,F, and H stereo-pairs. A-C, SAMP30240. D,E, SAMP30241. F,G, SAMP30242. H-J, SAMP30243 . K,L, SAMP30244. M,N, SAMP30245. O,P, SAMP30246. O,R, SAMP30247.
Description. The characteristic mace-shaped spicules are widely variable. The main structural elements of the spicules are radiating blunt tubercles that form the head of the 'mace' and usually also project further in one direction to form the shaft. Shaft length and thickness are subject to great variation (e.g., the gradation seen in Fig. 19D O-J-A-K-E-G). This variability seems due mainly to the number of tubercles that take part
in shaft formation. In a few spicules, the shaft may be hardly distinguishable from the head (Fig. 19G,V) or absent (Fig. 19T,U). The head often bears a few tubercles that are longer than the others. Sometimes these are ad jacent to the shaft (Fig. 190), but more often they are approximately opposite to the shaft (Fig. 19B,C,E,L) or oblique to it (Fig. 19D,R); such a ray may even form a 'counter-shaft' (Fig. 19V). Although the disposition of tubercles on the head
EARLY CAMBRIAN FOSSILS, S. AUST.
normally appears disorderly, weakly arranged transverse annulations may be visible. (Fig. 19B,
C,F,H).
In etched residues, spicules are preserved in phosphate. Fine structure of the surfaces (Fig. 19S) suggests that phosphate replicates an original crystallographic structure of elongated crystallites aligned in the directions of the in dividual tubercles.
37
gestive, but not sufficiently detailed to exclude the possibility that the spicules belong to another, possibly extinct, group. Spicule
A (Fig. 20) [SCM]
SAMP30269-72 from UNELI872, 1874 in the Ajax Lst., Mt. Scott Ra. Material.
Description. Shaft smooth, elongate (Fig: Spicule morphology does not ex 20E,F,H) with a circular cross-section, and one clude a sponge affinity. However, known cal end terminating in an expanded base (Fig. 20A careous sponges typically have simpl�r spicules J). The opposite end is always incomplete. The consisting of single crystals of calcite with base lies at an oblique angle to the shaft (Fig. uniform direction of the crystallographic axis 20C,I) and bears either a central depression or throughout the spicule (Jones, 1970). In contrast, transverse furrow that divides the base into two the structure of the Microcoryne spicules sug units that lie at different angles to the shaft (Fig. gests elongated elements aligned with th� 20B-D). Original mineralogy is not certain, but tubercles. .. phosphate appears to form a steinkern and coat Octocoral,sclerites are typically club- or ing around a former calcareous waH. spindle-shaped and warty, with the warts com monly arrang�d in transverse rows. Remarks. Their appearance recalls zhijinitids but A comparison with the various octocoral scler such a resemblance may be superficial. Similar ites figured by Bayer (1956) suggests particular spicules were described as Cambroclavus clavus resemblances with certain gorgonacean sclerites from the. Rhombocorniculum cancellatum and such as those of lunceella juncea (cf. Bayer, Microcornus parvulus Zones of Kazakhstan 1956, fig.154:2). Furthermore, most octocoral : (Mambetov & Repina, 1979) but their identity as sclerites are composed of acicular calcite crystals cambroclaves may also be questioned. The af aligned with the spicule axes or along the axes of finity of these spicules remains problematic. more prominent tubercles. These crystals may be distinctly visible on the spicule surface and thus Other spicules (Fig. 21) [SB] may be directly compared with spicules of M. cephalata (cf., e.g., Bengtson, 1981, figs 9F,10D These comparatively rare spicules are of un with Fig. 19S). known affinity. They appear to have beensecon OC.tocoral sclerites, although common in many darily phosphatized, and are assumed to have modern marine sediments, have a sparse fossil been composed of calcium carbonate. One type record. Only one example is previously known (Fig. 21A) is common in didemnid tunicates from the Palaeozoic, namely the Silurian Atrac (Lafargue & Laubier,1980; and discussion above undecMicrocoryne) , whereas the globular one tosella (Bengtson,1981). However, the occur rence of a probable gorgonacean axial skeleton (Fig. 21C) may possibly be an abraded center of in the Ordovician (Lindstrom,1978) and the in a ray-bearing spicule. Polyactine spicules (Fig. terpretation of certain Ediacaran frond-like fos 21D,E) are of a more normal sponge type, and sils as octocorals with pennatulacean affinities may belong to heteractinids. (Jenkins,1985) would not make octocoral sclerites in the Lower Cambrian of Australia COELOSCLERITOPHORANS [SB] unexpected. Comparisons may also be made with the aragonitic spicules of certain modern ascidians. Characteristic and unique to the Cambrian are a These may have a similar morphology to group of hollow calcareous sclerites with a scale Microcoryne spicules, in that they are built up of or spine-shaped distal part and a restricted basal radiating tubercles or spines, somewhat like the foramen. They include morphologically very heads of the latter form (Van Name,1945; Lafar- different fossils; two such groupings are com gue & Laubier,1980). This type of ascidian monly referred to as chancelloriids and sachitids, spicule, particularly typical of the Didemnidae,. the latter including the halkieriids, wiwaxiids, however, is generally 25-75 J.Lm in diameter, c. . and siphogonuchitids. Chancelloriids typically 1/10 Microcoryne spicules. have composite, star-shaped spicular rosettes; It may not be possible to establish the affinities·· , of Microcoryne with absolute confidence. sclerites in tight integration. Bengtson & Missarzhevsky (1981) pointed out Resemblances with octocoral sclerites are sugDiscussion.
j
38
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS,S. AUST.
that all of these sclerites were fundamentally similar. The sclerites in the different groups formed a scaly or spiny armour covering the body surface. They were hollow with a calcar eous wall, and did not grow by simple accretion but were shed or augmented by interpolation. Qn this basis a major taxon, the Coeloscleritophora, could be defined, apparently arising near the Precambrian-Cambrian transition, with a major diversity in the Early Cambrian, and becoming extinct in the Late Cambrian. The concept of the Coeloscleritophora as a major monophyletic taxon has so far not been wide ly accepted. Fe w p u b l i c a t i o ns have employed the concept in systematic treatments, but neither has there been substantial criticism. Vasil'eva (1985, p.115) regarded the concept as questionable, but did not substantiate her objec tions. Dzik (1986, p.126,127) similarly regarded the c hancelloriids as unrelated to the sachitids, but in stating that chancelloriids are hexactinel lids, triradially symmetrical, and resembling Anabarites, he demonstrated unfamiliarity with the data. His alternative proposal of grouping the sachitids with tommotiids, machaeridians, and hercolepadids on the basis of morphological· resemblances between imbricating sclerites, neglects sclerite histology. The South Australian sections investigated by us contain a large number of well-preserved coeloscleritophoran sclerites, representing chan celloriids and sachitids as well as forms not ob viously belonging to any of these groups, but clearly related to them. The morphological gap between chancelloriids and sachitids now ap pears to be filled, and new evidenc� on the fine structure of the sclerites supports structural and phylogenetical unity within the coelosclerito phorans..
Approaches to the study of coeloscleritophorans Although the notion that each animal had a com plex exoskeleton, composed of a large number of individual sclerites, is .firmly established and seems to be questioned only by Jiang (1984a; in Luo et al., 1982), this has seldom left any trace in the systematics. The practice of selecting a limited number of sc1erites from a sample and
39
assigning them to form taxa, has led to t,axonomic inflation. In combination with inade quclte illustrations of poorly preserved specimens (fragments, internal moulds) this practice precludes identification of biological taxa from published literature. For this reason, it is not possible to provide reliable synonymy lists of coeloscleritophoran taxa herein;· the suggested synonymies are incomplete and tentative. Scleritome analysis is mainly based on pattetns of co-occurrence and on structural charac teristics of individual sclerites. In the case of chancelloriids and halkieriids, comparisons may also be made with related forms preserved else where as complete exoskeletons (Bengtson & Conway Morris, 1984). In addition, the tightly integrated halkieriid scleritome offers the pos sibility of interpreting morphological features of the individual sclerites in terms ofju;xtaposition (e.g., facets). . Many· coeloscleritophoran taxa are known in the literature only from internal moulds. Because of the originally calcareous composition, this is a common typ· treated samples. The morphology of internal moulds, however, is insufficient for recognition of coeloscleritophoran taxa. Internal structlJre of the .walls and cavities is, on the other hand, of great importance for· understanding their origin '. and composition. -
.
,
.
Suprageneric taxonomy Due to our inadequate knowledge of coeJoscler itophoraq biology and phylogeny, conflicting suprageneric taxonomies are available. The various categories applied for sachitids were reviewed by Bengtson & Conway Morris (1984) who recognized the Order Sachitida He, 1980, containing the Halkieriidae Poulsen, 1967, Wiwaxiidae Walcott, 1911, and Siphogonuchit idae Qian, 1977, and the Order Chancelloriida Walcott; 1920 (nom. trans!., Sdzuy, 1969), con taining only the Chancelloriidae Wa1cott, 1920. The dichotomy between Sachitida and Chancel loriida is implicit by these two groups being usually treated in the literature as separate and unrelated (the Chancelloriida have traditionally been regarded as heteractinid sponges). This division within the Coeloscleritophora is also
Fig. 19. Microcoryne cephalata Bengtson,gen. et sp. nov.,Mt. Scott Ra.,Ajax Lst.,UNEL1874. All x50 except for S. A-O stereo-pairs. A,holotype,SAMP30248. B, SAMP30249. C,SAMP30250. D, SAMP30251. E, SAMP30252. F, SAMP30253. G, SAMP30254. H, SAMP30255. I, SAMP30256. J; SAMP30257. K, SAMP30258. L, SAMP30259. M, SAMP30260. N,SAMP30261.-0, SAMP30262. P, SAMP30263. Q, SAMP30264 (questionable assignment). R,S, SAMP30265. S,x1000,detail, position indicated in R. T, . SAMP30266. U,SAMP30267. V, SAMP30268.
40
STEFAN BENGTSON et al.
Fig. 20. Spicule, Fonn A: Mt Scat! Ra., Ajax Lst., UNEL1872. A,B, SAMP30269, x90. C-E, SAMP30270. C,D, x120. E, x90. F,G, SAMP30271. F, x90; G, x120. H-J, SAMP30272. H,I, x90. J, x120.
supported by differences in the fine structure of the sclerites. However, discovery of typical chancelloriids with isolated rays (Eremactis gen. nov., and probably Monospinites Sayutina in Vasil'eva & Sayutina, 1988) and of halkieriid like for ms (Hippopharangites gen. nov.) with sclerites approaching the morphology of isolated chancelloriid rays suggests that the dichotomy must be defined by characters other than the single or composite sclerite arrangement. The problem of theSachitidae. The Sachitidae is commonly synonymized with the Halkieriidae (cf. M i ssarzhevsky & M a mb e tov, 1981; Bengtson & Missarzhevsky, 1981; Bengtson & Conway Morris, 1984), but it is not clear that the Sachitidae are sachitids at all, i.e. that they belong to the Sachitida as defined here. The problem has to do with uncertainties surround ing Sachites Meshkova, 1969 w hich originally
included S. proboscideus Meshkova, 1969 as type, and S. sacciformis Meshkova, 1969. Both holotypes are internal moulds. Whereas the holotype of S. sacciformis seems to represent a palmate sclerite of a halkieriid (Bengtson & Con way Morris, 1984), the nature of the holotype of S. proboscideus is less clear. Meshkova (1969, p1.52, fig.l) illustrated the proximal and middle parts of the internal mould of a sigmoidally curved sclerite in lateral view. The proximal end of the sclerite curves through c. 90°, there is a pronounced basal facet, but the foramen is not visible. I1I ustrated paratypes (Meshkova, 1969, p1.52, figs 2,3) indicate a rounded foramen about 1/3 of the width of the basal facet. The descrip tion (Meshkova,1969, p. 165) states that the transverse section is oval near the base and dis tally round (see also Matthews & Missarzhev sky, 1975, p1.3, figs 9,10; pIA, figs 3,6; Fig. 22). Meshkova's (1974) referrals of other sclerites
EARLY CAMBRIAN FOSSILS, S. AUST.
41
Fig. 21. Spicules. Kulpara Lst., Horse Gully, 6429RSI05. All x180, except B. A, D, and E stereo-pairs. A,B, SAMP30273. B, detail of A, x5000. C, SAMP30274. D, SAMP30275. E, SAMP30276.
42
STEFAN BENGTSON
et
al.
to S. proboscideus seem highly questionable. In particular, a specimen from the type locality of Titiriktehehkh (Meshkova,1974, pI. 25, figs 1,2) is a halkieriid cultrate, and was reassigned to H. trianguliformis Mambetov in Missarzhevsky & M ambetov,198L The remaining material (Meshkova,1974) from the Aldan and Olenek Rivers is fragmentary, but one specimen (Mesh kova,1974, pI.25; figs 5,6) is a cultrate base. Although the internal cavity in cultrate halkieriid sc1erites frequently is narrower and more rounded than the exterior blade, moulds il lustrated in Meshkova's 1969 paper and herein (Fig. 22) do not seem consistent with a cultrate sclerite, particularly in the flat basal facet of the former. A specimen illustrated as S. proboscideus from the Meishucunian of Yunnan by Jiang (in Luo et aL, 1982, pI.16, fig. 7) is evidently a halkieriid sclerite. The great majority of other species referred to Sachites are also better placed in Halkieria (see also Mambetov in Missarzhevsky & Mambetov, 1981). S. ningqiangensis Yue (in Xing et al., 1984b, pI. 27, figs 24, 25) from Shaanxi, China, may be a true Sachites, but other assignments' to. this genus are highly ques tionable. One specimen ofS. hastatus (He in Yin et al.; 1980, pl.18, fig.9) maybe a zhijinitid, but the other (his pl.18, fig. 30) is not identifiable. The status. of S. directus (Mostler, 1980, p1.2, fig.6) seems questionable. Fedorov (1984) erected S. meshkovae (generic name consistently. misspelt Sachithes), and transferred a specimen previously assigned to S. sacciformis (Meshkova 1974, p1.25, fig.19). While there is little doubt that Mes�kova's (1974) specimen belongs to Halkieria, Fedorov's (1984, pl.1, figs 16,17) are only questionably assigned on the basis of the . available illustrations. The scleritome of Halkieria sp. from the basal Tommotian of the River Aldan contains also a minor number (c. 5%) of spiniform sc1erites (Bengtson & Conway Morris, 1984). They have a laterally expanded base which differs markedly from the flat basal facet in S. proboscideus. Similarly, spiniform elements in the halkieriids described herein do not suggest close com parison with S. proboscideus. The sclerites described by Meshkova (1969) as S. proboscideus may represent spini f o rm sclerites from the same animal as pal mates described as S. sacciformis. However, a scleri tome analysis of S. proboscideus/sacciformis cannot be carried out from published' data, be cause only a few internal moulds from different geographical regions have been figured. Further more, the holotype of S. sacciformis has been figured in three different publications as coming from three widely separated geographical .
regions (Bengtson & Conway Morris, 1984, p.312). Thus the nature of Sachites and the Sachitidae remains dubious. If S. sacci/ormis is based on palmate sclerites of S. proboscideus, the genus should be referred to the Halkieriidae and may be a synonym of Halkieria. If, on the other hand, S. proboscideus sclerites represent an animal without scale-shaped (palmate and cultrate) sclerites, Sachites may be more closely allied to Hippopharangites a n d Eremactis, a n d t h e Sachitidae is valid. I n view of the morphological similarities between sclerites of Hippopharan gites and those of Siberian Sachites figured herein, we follow the latter course and recognize Sachitidae Meshkova,1969, as a separate coeloscleritophoran family, distinct from the Halkieriidae.
The' problem of the Siphogonuchitidae. The Siphogonuchitidae Qian,1977, is a typical com ponent of the Meishucunian of China and has also been reported from Mongolia (Voronin et al.,1982), Iran (B. Hamdi, pers. comm. 1986), and France as Halkieria sp. 3 (Kerber,1988). A number of siphogonuchitid taxa have been erected on the basis of mor phology of individual sclerites. No complete specimens have been found, but occasionally several sclerites may be found as aggregates (Chen,1979a; Voronin et al.,1982; Yang, He & Deng, 1983; Qian & Bengtson, 1989). Qi an & Bengtson (198 9) illustrated and described abundant and well-preserved assem blages of siphogonuchitids from the Meishucu nian of Yunnan, in order to establish the mor phological variability and structure of co-occur ring sclerites. Siphogonuchitid sclerites are typically hollow, elongate, asymmetrical, ir regularly polygonal in cross-section, having a surface sculpture of longitudinal ridges and transverse lineations, and with a fairly large basal opening that is often elongate in a'plane perpen dicular to the plane of flattening of the distal parts of the blade. Although the transerse markings often have the appearance of growth lines, the modifications of the basal end and the evidence of progressive mineralization in distal direction indicate that apart from the unrestricted basal opening siphogonuchitids conform to the coeloscleritophoran mode of sc1erite formation (Qian & Bengtson,1989). The halkieriid scleritome may contain sc1erites superficially similar to siphogonuchitids. Bengtson & Conway Morris (1984, p.316, fig. 6A-C) discussed such sclerites from the Siberi an Platform. Th�s study of Australian halkieriids has identified siculate and spiniform sclerites of Thambetolepis (Figs 56-61) and Halkieria (Fig.
EARLY CAMBRIAN FOSSILS, S. AUST.
43
Fig. 22. Sachites proboscideus Meshkova, 1969. River Rassokha, Siberian Platform, Tommotian Stage, coIl. N.P. Meshkova, sample 241. All x25, except C and F. A-C, SMNHX3251. C, detail of A, x500.. D-F, SMNHX3252. F, detail of D, x500.
47) that, if f ound b y themselves, might well have been identified as siphogonuchitids. In spite of this morphological similarity, a fundamental dif-
ference in scleri te articulati on is evident: halkieriids had a regular mail of imbricating sclerites, whereas in siphogonuchitids the
44
STEF AN BENGTSON
et al.
Fig. 23. Chancelloria racemifundis Bengtson, sp. nov., Parara Lst., Curramulka, UNEL1846. All x50, except where otherwise indicated. A, stereo-pair. A-D, SAMP30277. B, detail of A, x250. D, detail of C, x 1000. E-H, holotype, SAMP30278. F, detail of E, x250. H, detail of G, xlOOO.
EARLY CAMBRIAN FOSSILS, S. AUST.
sclerites were arranged in complex bundles, al though their'articulation facets' probably derive from an early non-mineralized stage of sderite formation and are not functional in fully formed ' sclerites (Qian & Bengtson,1989). Eve n so, siphogonuchitid and halkieriid sclerites may be easily confused, particularly if preservation is incomplete. Details of morphol ogy may help; for example, lateral canals in the siphogonuchitid-like siculate and spiniform sclerites of Thambetolepis (Figs 56--61) identify them as belonging to the same form as the as sociated broader (palmate and cultrate) scler ites. Surface ornamentation may be useful in relating co-occurring sclerites to each other but is no absolute indicator to the identity of scler ites, as similar sculptures' consisting of imbri cating scale-like tubercles may occur in halkier iids (Fig.S9Q,R), siphogonuchitids (Qian & Bengtson; 1989, fig. 13E 6-8), sachitids (Fig. 38D,E) and even chancelloriids (Fig. 29A-C).
an extension of the extraspi�ular spongIn skeleton. Goryansky (1973), arguing against the sponge hypothesis, consigered 'that the sclerites �c�n� siste"d of a phosphate-carbonate compound WIth no internal cavity. Although Goryansky was probably correct in regarding the, sclerites as external, his interpretation of their fine structure and composition cannot be upheld (Qian & Bengtson,1989). Evidence for a thin calcareous wall surrounding separate inner cavities appears irrefutable (Sdzuy,1969, pL1,5, figs 3,8a; Figs 37, 174F,G). Bengtson & Missarzhevsky (1981) pointed out that this sclerite structure precludes an involvement by enveloping, sclerocytes of sponge type and suggests that the sclerites were secreted as mineralized sheaths on organic precursors. Consequently, the scler ites can hard ly be homologous with spicules as in living groups of sponges. This point of view was also accepted by Rigby (1986, p.13). _
Composition of the chance.zloriid scleritome
CHANCELLORIIDS [SB] Chancelloriid sclerites are typically composite, having 2 to 20 radiating marginal rays and some times a central ray. Each ray is a separate unit with its own wall. Consequently, in the zones of ray contact the inner cavities of adjacent rays are s e parated b y a d o u b l e c a l c a r e o u s w a ll (Sdzuy,1969, pl.16, fig.7b; Figs 37B, 174F,G). The foramen of each ray faces the same direc tion, so there is a basal facet with a polygonal pattern of sutures separating the surfaces with the individual foramina (Figs 26G,M, 30A). Chancelloriid sclerites are often preserved as internal moulds, but as the walls between ad jacent cavities are thin, the rays often adhere even after acid-etching. To designate ray structure of individual sclerites we use a simplified version of Sdzuy's (1969) system. We do not use 'V' (vertical) and 'H' (horizontal) to denote rays, but simply'n+n' to state the number of marginal versus central rays in the sclerite. Thus a '4+0 sclerite' has four marginal and no central ray, and '6-8+ 1 sclerites' have six to eight marginal and one central ray. Chanc e l l o r i i ds h a v e tradit ionally b e e n regarded as sponges (Walcott,1920), and Sdzuy (1969) envisaged them as a stem group of the three major grOups of living sponges, i.e. the Hexactinellida, Demospongea, and Calcarea. He regarded the internal cavity of the chancelloriid sclerites as homologous to the axial canal in demosponge and hexactinelIid spicules, and sug gested that they were filled via the foramen with
45
,
Most chancelloriids are found in the rock as dissociated sclerites, but a number - of natural assemblages are known (Walcott,1920; Sdzuy, 1969; Rigby,1978), mostly from the Middle Cambrian. The specimens from the Burgess Shale that Walcott (1.920) included in'the type species, C. eros, incorporate several ta;xa with different types of scleritomes. Restudy of Walcott' s type series (pers. obs.) indicates at least/ three, probably more, taxa, l)amely: 1, a form with conical body shape and "two types of star-shaped sclerites; common 6-7+1 ones and rare 4+0 ones with the four rays perp endicular to each other in the plane of the body surface. This form includes the lectotype of C. eros (designated Gorya�sky, 1973, p.43), figured by Walcott (1920;' p.l86, fig.2, p1.88, fig. IQ. Walcott's figures of the ]ectotype do not show the whole specimen and may give the impression that it could be a chance assoGiation of sclerites, but the discrete outline of the body and two layers of sclerites facing opposi�e direc tions leave no doubt that it is a body fossil. Rigby (1978) also found a 4+0 sclt�rite in a cluster of C. eros from the Middle Cambrian of Utah. Mostler -& Mosleh-Yazdi (1976) reported 4+0 sclerites ('Chancelloria n.sp.') in associa tion with sclerites of eros-Jype (7+ 1; described as 'C. iranica n.sp. ') from the Upper Cambrian of Iran. This association probably represents a species closely related to or identical to C. erOSe Walcott's (1920, p. 331,332) remark that rectan gular spicules with four slender rays are· as sociated with C. drusilla sclerites .should also be noted in this context. Walcott referred these
46
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
47
spicules with a question mark to Protospongia; . Middle Cambrian forms there.is little variation they now need to be re-investigated. in ray number within' a single scleritome, in 2, a form with narrowly conical body and comparison to the considerable' variability slender,3+0 sc1erites with two rays parallel to the shown by samples of disarticulated sclerites in body surface and the third curving out from it. Lower Cambrian rocks. Our South Australian All rays appear to be recurved toward the broader samples yielded chance�loriid spicules ranging end of the body, although the protruding ray is from 0+1 to 11+1 and from 3+0 to 8+0, and us ually broken off. Walcott ( 1920, p1 .88, variability is considerable even within a single fig.1,la,d,e) illustrated examples of this form. sample (Table 1). 3, a form with narrowly conical body and 4+0 Patterns of co-occurrence of the Australian sclerites with three rays in the plane of the body chancelloriid sclerites suggest a limited number surface and one protruding from it. As with the , of taxa, but the great variability militates against previous form all four rays appear to point a stable taxonomy. We concentrate on relation toward .the broader end of the body, but the ships of chancelloriids with other· coelo protruding one is usually broken at the base. This scleritophorans and on mode of sclerite form form was illustrated by Wa1cott (1920, p1.88, ation. Taxa recognized are based on small num fig.1c). bers of characteristic sclerite types, and the scleritome interpretation is based on co.. occur Walcott (1920) interpreted the sc1erites of rences of sclerites of similar structure and forms 2 and 3 as the same type as those of the general morphology rather than ray number. lectotype, but buried at an angle so that some of With the exception of Archiasterella hirundo the rays are not visible. This interpretation is not and the monorayed Eremactis, each species de correct because the sc1erite shape in the three facto has sc1erites of highly variable ray number. forms is consistent, and particularly form 2 has Whether or not such a 'liberal' interpretation of the scleritome structure is valid needs further more slender rays than the lectotype of C. eros. The form 2 sclerites resemble those described as investigations. Allonnia tripodophora by Dare & Reid (1965 ) from the Lower Cambrian of France. Family CHANCELLORIID� Walcott, 1920 A few other species of chancelloriids are known from natural assembla ges. Sc1erite Included genera. Chancelloria Walcott,1920, Aldania Vasil 'eva, 1985 (non Moore, -1896) clusters of C. pentacta were described by Rig by (1978) from the Middle Cambrian of Utah. (=Archiasterella); Allonnia Dore & Reid, 1965 ; Archiasterella pentactina, based on one probab Archiasterella Sdzuy, 1969; Dimidia Jiang in ly natural sclerite association and a number of Luo et al., 1982 (?=Allonnia); Diplospinella. isolated sclerites, is from the Lower Cambrian of Vasil'eva in Vasil'eva & .Sayutina , 1988; Spain (Sdzuy,1969). Further species have been Eremactis gen. nov.; Fangxianites Duan, 1984 based on rich spicule assemblages (e.g., Zhurav (?=Chancelloria) ; Monospinites Sayutina in Vasil 'eva & Sayutina, 1988; Onychia Jiang in leva & Kordeh, 195 5 ; Sdzuy, 1969). Although the composite nature of the sc1eritome and the Luo et al., 1982 (non Blainville, 1823; Huebner, variability of sclerites have been known since 1825; Haliday, 1829-1830; Sandberger, 1889) (?=Allonnia); Rosella Vasil'eva in Vasil'eva& Walcott'stime, some recent taxonomic schemes proposed taxa defined by a single sc1erite type Sayutina, 1988 (non Cossman, 1925 ) (?=Chan celloria); Stellaria V a s il ' e v a , 1 9 8 5 (non (Jiang in Luo et al., 1982; Vasil'eva& Sayutina, Schmidt, 1832; Nardo, 1834; Bonaparte, 1838) 1988). The number of rays in the sclerites may show (?=Chancelloria). slight (C. pentacta, C. eros) to considerable (C. maroccana) variability. Also, some species may Diagnosis. Coeloscleritophorans with armour have several types of sclerites in their scleritome consisting of spiny sc1erites. Sclerites usually - as mentioned above, C. eros has sporadic 4+0 composite, consisting of individual rays joined sclerites among the normal 6-7+1 ones, and A. at base but having separate internal cavities and pentactina, in addition to the normal 4?-5+ 0 has foramina. Cross-section of rays nearly circular, a small percentage of 2+0 sc1erites (Sd zuy, except where bases are joined. Foramen re 1969). Nevertheless, it is remarkable that in the stricted.
Fig. 24. Chancelloria racemifundis
Bengtson, sp. nov., Mt Scott Ra., Aj ax Lst., UNELI866. All x50, except where other wise indicated; A, stereo-pair. A-D, SAMP30279. C, detail of B, x150; D, detail of C, xIOOO. E,F, SAMP30280. F, detail of base, x150. G,H, SAMP30281. 1,1, SAMP30282.
48
STEFAN BENGTSON et al.
F ig. 25. Chancel/aria racemifundis Bengtson, sp. novo SAMP30283, Parara Lst., Curramulka, UNEL1848. A, x75. B, stereo-pair, detail of A, x450. C x75. D, detail of C, x450.
Taxonomic comparisons. The Chancelloriidae appear to be most closely related to the Sachiti dae, but distinction between the two families is not clear, due to imperfect knowledge of Sa chites. On the basis of Hippopharangites, we interpret sachitids to have had a differentiated scleritome that formed a scaly cover approach-
ing the type present in the Halkieriidae and Wiwaxiidae, whereas sclerites of Chancellorii dae typically formed projecting spikes. Chancelloria Walcott, 1920 * 1984
Fangxianites Duan, p.168.
EARLY CAMBRIAN FOSSILS, S. AUST.
Type species. Chancelloria eros Walcott,1920 from the Middle Cambrian Burgess Shale of British Columbia.
?*1985 Stellaria Vassil'eva, p.120. non 1832 Stellaria Schmidt. non
1834 Stellaria Nardo.
non
1838 Stellaria Bonaparte. Rosella Vassil' eva in Vasil' eva & Say utina , .
?1988 non
Other Lower Cambrian species. C. aldanica Zhuravleva & Kordeh,1955; C. altaica Roma nenko,1968; C. arida Duan,1984; C. asteroidea
p.197. 1925 Rosella Cossman.
Vertical :
OV
Lateral:
1V
3
4
UNEL1851
•
•
•
UNEL1849
•
•
•
UNELl848
•
•
•
UNEL1847
•
•
•
UNEL1846
•
•
UNEL1845
•
•
• •
•
•
1
2
49
5
6
7
8
9
3
4
5
6
7
8
9
10
11
12
13
Curramulka NMVPL95 •
•
•
•
•
••
•
•
•
• •
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• •
•
•
•
Horse Gully 6429RS1l3 6429RS112
•
UNEL1852
•
6429RSll1 UNEL1853
•
•
•
•
•
• •
•
•
•
•
•
•
•
•
6429RS109 6429RS108
•
•
•
•
•
• •
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
6429RSI07
•
•
•
6429RSI10 UNEL185A
•
•
•
UNEL1855 UNEL1856
•
•
6429RSI06 UNEL1857
•
•
•
•
•
•
6429RS100
•
•
•
•
•
•
I
Kulpara 6529RSl13
•
•
6529RSI05 6529RSI04
•
•
•
•
•
•
•
•
•
?
•
?
? ?
6529RSlOO 6529RS99
Mt. Scott Ra. UNEL1874
•
UNEL1873
•
•
UNEL1872
•
UNEL1871
•
UNEL1870 UNEL1869
•
UNEL1866
•
•
•
•
•
•
•
•
•
•
•
•
• •
•
•
•
•
•
•
•
• •
• •
•
•
• •
•
•
•
•
•
UNEL1867 UNEL1865
•
•
•
•
•
•
•
• • • • •
•
•
• • •
?
.J'
Table 1. Distribution of chancelloriid sclerite types in some samples. Categories refer to number of vertical and lateral rays.
50
S TEFAN BENGTSON et al.
Fig. 26. A-K , Chancelloria? spp. Mt. Scat! Ra.,Ajax Lst., UNEL 1866.All x30 except F and K.Ais a ste reo-p air. A, SAMP30292. B, SAMP30293. C,D, SAMP30294. E,F, SAMP30295. F, detail of E, x300. G, SAMP30296. H, SAMP30297. I-K, SAMP30298. K, detail of J, x300. L-N,Allonnia cf. tri podophora Da re & Reid , 1965. UNEL1866. All x30. L,M, SAMP30299. N, SAMP30300.
EARLY CAMBRIAN FOSSILS, S. AUST.
(Vasil'eva in Vasil'eva & Sayutina, 1988); C. coronaceaVasil'eva: 1985; C.exilis Saito, 1936; C. fragilis Va si!' e vcl, 1 9 8 5 ; C. grosdilovi Zhuravleva & Kordeh, 1955; C. hispanica (Sdzuy, 1969); C.lenaica Zhuravleva & Kordeh, 1955; C. maroccana Sdzuy, 1969; C. odontodes Duan, 1984 (C. arida); C.? petalina (Duan, 1984) (=C.? schizoloma); C. sardinica Mostler, , 1985; C.? schizoloma (Duan, 1984); C. spinulosa Vasi!' eva, 1985; C. symmetrica Vasil' eva, 1985.
Distribution. North America, Europe, Asia, Australia, Antarctica; Lower-Upper Camb!ian. Diagnosis. Radially symmetrical sclerites, with or without vertical rays, and with 4-12 lateral rays. Chancelloria racemifundis Bengtson, sp. nov. (Figs 23-25)
Etymology. L a ti n a dje c ti v e f o r m e d f r o m racemus, cluster of grapes,fundus, base, bottom, and the suffix -is, with; alluding to the common development of spherulitic structure in the basal regIOn. Material. Holotype SAMP30278 (Fig. 23E-H), from UNEL1846, Curramulka, Parara Lst.; c. 80 paratypes. Distribution. Curramulka, Parara Lst. (UNEL1846, 1848); Horse Gully, Kulpara and Parara Lsts (UNEL1857); Mt. Scott Ra., Ajax Lst. (UNEL1866). Diagnosis. Chancelloria with 3-7+0 and 511+1 sclerites with basal surface consisting of protruding walls between foramina and spheru litic deposits in and around the foramina. Description. Variation range of 3+0, 4+0 (Fig. 24E), 5+0, 6+0 (Figs 23A-D, 241,J, 25), 7+0, 5+1, 6+1 (Figs 23E-H, 24A-D), 7+1 (Fig. 24G,H), 8+1, 9+1, 10+1, and 11+1. The most common forms are 6+ 1. Sclerites of this species are generally small, about 1-1.4 mm in diameter, and slender. They tend to have a high lateral profile, particularly if lacking a central ray (Figs 23C, 24E). Some specimens, particularly larger ones, of similar basal morphology (Fig.25) have thicker rays of even taper. The base is characteristically a circular or botryoidal structure bounded by a distinct ridge (Fig. 24D), and with more or less high ridges on the basal surface marking the sutures between rays (Figs 23B,F, 24C,F, 25B,D). The surface is thus not flat as in most other chancelloriids, but
51
has a marked relief, the inter-ray ridges some times even forming spines (Fig. 24C,F). The basal surfaces 'outside the foramina are typically spherulitic, with spherules about 5-7J-Lm i n diameter (Figs 23B,D,F, 24C,D,F, 25B,D). The surface of the sclerites outside the base has faint striations longitudinal to the rays (Figs 23F, 24C,D,F) which presumably correspond to a fibrous or sheet-like intenlal structure of the wall (Fig. 24C,D). In addition, there are sometime� rod-like structures perpendicular to the surface (Fig. 23H); these may represent phosphatized tubules.
Taxonomic comparisons. Chancelloria tubercu lata Sayutina in Vasil'ev:a & Sayutina (1988, p1.30, fig.2; p1.32, fig.1)bas prominent tubercles associated with the basal facet of each ray, but in both figured specimens these are sit1!ated on the distal side of the foramina, whereas in C. racemifundis such spines occur in the junctions between rays. Chancelloria spp. (Figs 26A-K, 27, 28)
Description. Most common preservation of chancelloriid sclerites is as moulds of the inter nal cavity. A number of such sclerites are not readily referred to the species recognized herein but represent sclerites with a flat basis and a near radial symmetry. They. are figured herein as Chancelloria spp. from UNEL1866 (which is rich in chancelloriid remains). As the elaborate base in C. racemifundis is not well expressed on the internal moulds, some of these specimens (e.g., Fig. 26A-E, I-K) may represent this species. However, the. peripheral position of the foramina on the basal disk in some specime' (Fig. 27E) is not readily comparable' with G. racemifundis. The ray numbers represented in clude 3-8+0 and 3-11+1 forms.
Archiasterella Sdzuy, 1969
Type species. Archiasterella pentactina Sdzuy, ' 1969. Other species.A. antiqua Sdzuy, 1969;A. hirun do sp. nov.;A. robustaVasil'eva, 1985;A. tetrac tina Duan, 1984; A. tetractina. Vasil'eva & Sayutina, 1988 (non Duan, 1984). Diagnosis. Bilaterally symmetrical sclerites having no central ray, but sagitalIy positioned marginal ray recurved away from plane of well developed basal facet. Number of marginal rays usually 4 or 5; 2+0 sc1erites may also be present.
52
STEFAN BENGTSON et al.
Fig. 27. Chancelloria spp. Mt. Scott Ra., Ajax Lst., UNEL1866. All x30. A,B, stereo-pairs. A, SAMP30284. B, SAMP30285. C, SAMP30286. D,E, SAMP30287. F, SAMP30288. G, SAMP30289. H, SAMP30290. J, SAMP30291.
EARLY CAMBRIAN FOSSILS, S. AUST.
53
Fig. 28. Chancelloria sp. Parara Lst., Curramulka, UNEL1763B. All x75, except C and F. A,E, stereo-pairs. A-C, SAMP30301. C, detail oCB, x2000. D-F, SAMP30302. F, detail aCE, x450.
54
STEFAN BENGTSON
et al. \ /
Archiasterella hirundo. Bengtson, sp. nov. . (Figs 29, 30)
but lack the robust structure and flattened base. They are referred to asA. cf. hirundo.
Etymology. Latin hirundo, a swallow; referring to t.he bird-like profile of the sc1erites.
Taxonomic comparisons. B o t h A. tetractina Duan,1984, and A. tetractina Vasil'eva & Say utina, 1988, non Duan, 1984, have 4+0 sclerites. Those of Duan's species, however, appear to. have a considerably less developed bilateral symmetry than A. hirundo and lack the broad basal surface, even in large (2mm) specimens. The two figured specimens (Duan, 1984, pl.4, figs 3,4) appear to approach the more radially symmetrical sc1erites of A llonnia? tetrathallis (Jiang,1982) (Luo et al ,1982, pl.23, figs 1,2; cf. Qian & Bengtson, 1989, fig. 6). The two figured specimens of Vasil'eva & Sayutina's (1988) homonymously named species similarly lack a broad base. However, they are of the same size as the small ones referred herein to A. hirundo, which similarly lack this feature. Thus it is no.t possible to compare Vasil'eva & Sayutina's species with A. hirundo until more and larger specimens of the former have been described. A Burgess Shale specimen (Walcott,1920, pI. 88, fig.1c) of Chancelloria eros (type 3 above) has sclerites that approach the morphology of the slender specimens referred to Archiasterella cf. hirundo herein (Fig.29D,E). The Burgess Shale fossil has a constant ray configuration between sclerites. This supports the nQtion thatA. hirundo has a unimembrate sc1eritome, an interpretation based on the uniquely robust structure of A. hirundo sc1erites and their occasional occurrence in samples with no other chancelloriid sclerites present.
Material. Holotype SAMP30307 (Fig. 30D-F), Parara Lst., UNEL1848, Curramulka; c. 25" paratypes. \
Distribution. H o r s e Gul l y , P a r a r a L s t . (UNEL1856, 1854, 6429RS110, UNEL1853, UNEL1852, 6429RS112, 6429RSI13); Curra mulka, Parara Lst. (UNELI845, 1846, 1847, 1848,.1849, 1850(?), 1851); Kulpara, Parara Lst. ( 6 5 29RS1 0 5 ) ; Mt . S c o t t R a . , A j a x Lst. (UNELI866, 1869, 1870, 1871, 1872, 1873)." Diagnosis. Archiasterella with 4+0 sclerites having one short median recurved ray, one longer median ray, and two lateral recurved rays. Sc1erites robust and somewhat flattened. Basal area large, flat, with large foramina, particularly on the longer median ray. Surface sculpture of inclined tubercles. Description. Sclerites (4+0) are distinctly bilat erally symmetrical. Two rays are in the plane of symmetry, the anterior (arbitrary definition) one more or less recurved upwards and backwards, while the posterior ray is long and usually straight. The- two lateral rays are more or less recurved posteriorly and of varying length in relation to the other rays. The lateral rays typi cally m�eet in a sagittal suture, so that the median rays are not in contact (Figs 29A,F, 30A,D). The basal surface is strongly developed, so that the lower side of-the sc1erites is typically broad and flat (Fig.30A,B). Foramina vary in size, but commonly the foramen of the posterior ray is excessively developed, taking up most of the basal surface. The inne! edge of the foramen is nearly straight. Some specimens show a pattern of arched wrinkles on the basal surface adjacent to. the straight edge (Fig. 30C). The surface pattern on the upper side of the sc1erite consists of distally directed tubercles, c.10-20J.Lm thick and 2�0J.Lm long (Figs 29C, 30F). They are sparsely distributed, sometimes tending towards arrangement in transverse rows. The flat lower surface lacks tubercles: Some specinie" general ray configuration as typical A. hirundo,
.
Allonnia Dore & Reid, 1965
Allonnia Dort� & Reid, p.20. ?*1982 Onychia Jiang in Luo et al.,p.198. non1823 Onychia Blainville. non1825 Onychia Huebner. non1829-30 Onychia Haliday. non1889 Onychia Sandberger. ?*1982 Dimidia Jiang in Luo et al., p.198. nom. nudo ?1982 Diminia Luo et al., p.259. *1965
Type species. Allonnia ti-ipodophora Dore & Reid,1965. Other Lower Cambrian species. A. erromenosa Jiang in Luo et al., 1982; A. rossica (Sayutina in Vasil' eva & Sayutina, 1988); A.? simplex (Hang
Fig:29. A-C, Archiasterella hirundo Bengtson, sp." nov.SAMP30303, Parara Lst., Kulpara, 6529RS105. A, stereo':pair� x50. B, x50. C, detail of B, x500. D,E, A. ef. hirundo. SAMP30304, Mt. Seott Ra., Ajax Lst., UNEL1866.D, stereo-pair, x30. E, x30. F,G, A. hirundo. SAMP30305. Same sample as D,E, x30.
EARLY CAMBRIAN FOSSILS, S. AUST.
55
56
STEFAN BENGTSON et al.
. )
57
EARLY CAMBRIAN FOSSILS, S. AUST.
in Luo· et al., 1982); A.? stelliformis Vasil' eva, 1985; A .? tetrathallis (Jiang in Luo et ai., 1982).
Diagnosis. Chancelloriids with 3+0 (possibly also 2+0 and 4+0) sclerites, the rays of which bend sharply away from the plane of the basal facet. Remarks. See Qian & Bengtson (1989) for dis cussion of Onychia Jiang in Luo et al., 1982 and Dimidia Jiang in Luo et al., 1982. AlIonnia cf. tripodopbora Dore & Reid, 1965 (Fig. 26L-N)
Material. About80 specimens. Distribution. C u r r a m u l k a , Parara Lst. (UNEL1847-1851); Horse Gully, Parara Lst. (UNEL1863, 1854, 1856, 6429RS 108, 6429 RSl12); Kulpara, Parara Lst. (6529RS104-105, 6529RS113); Mt. Scott Ra., Ajax Lst. (UNE L1866, 1867, 1871, 1872). Description. Sclerites have 3 equal rays, up to c. 2mm long, diverging at 1200 from each other and at c. 10-450 from the basal plane. The foramina are small and round. Taxonomic comparisons. Detailed comparisoJ).s with other taxa are precluded because the specimens are internal moulds. Scleritomes of other chancelloriids may contain 3-rayed scler ites(as suggested forC. racemifundis above), but . the preserved bodies of chancelloriids with 3rayed sclerites in the Burgess Shale (type 2 of the Burgess eros) suggest that some forms with Al lonnia-type sclerites may be unimembrate. The type pictured herein is of a generally larger size, and may represent a separate taxon. Morphologi cal distinction between these scler ites and those that most probably belong to other chancel loriids, is not clear. Eremactis Bengtson & Conway Morris, gen. nov. [SB, SCM]
Etymology. Greek eremos, solitary, and aktis, ray, referring to the sclerites generally having one ray. The name is feminine in gender. Type species. Eremactis conara sp. novo Other species.E. mawsoni sp. novo
Diagnosis. Coeloscleritophorans with elongate sclerites, circular cross-section. Occasionally two sclerites fused to form chancelloriid-like composite� Foramen rounded, with irregular margin, set off from· rest of sclerite by constric tion formed by· a coricave region around the· foramen. Sclerite surface smooth or with weak longitudinal striations. Wall built up of distinct, longitudinally and radially oriented, sheet-like elements. Basal surface often with spherulitic structures.
Affinities. As in Hippopharangites and presum- . ably other members of the Sachitidae, sclerites of Eremactis neither fused as a chancelloriid like rosette nor articulated in an integrated halkieriid arrangement. They resemble · isolated chancelloriid spicules, and the occasional twin sclerites of E. conara lend further creden·ce .,this comparison. The common occurreI.1ce of spherulitic basal deposits also recalls the chan celloriid condition. Eremactis sclerites -differ from those of Hippopharangites in being more consistently cylindrical, smooth, and having a· larger, clearly marked aperture set in a markedly concave apertural region. Sayutina (in Vasil'eva & Sayutina,1988) described Monospinites, based on club-like ray� suggested to be of 'chancelloriid type. Although her illustrations (Vasil'eva & Sayutina, 1988, pI. 31, figA) of the only species, M. simplex, are too poor to establish its chancelloriid nature,. this seems to be a likely interpretation. We therefore tentatively accept Monospinites as a chancel10riid. Generic distinction from Eremactis is warranted by different shape of the cylindrical . rays of the latter genus. _
"
Preservation. . Although the sclerites are phos phaJized, aswjth other coelosc1eritophorans this is evidently diagenetic · replacement of a cal careous skeleton. Specimens may occur as steinkerns of the central cavity, but more usual ly at least portions of phosphatized wal1 adhere. Apparent remains of shell ultrastructure are recognizable both on the steinkern surface and in . the wall. Occasionally the wall occurs' without any steinkem filling, and in other instances there is an indicatioJ). of an epitaxial.coat that serves to mask some finer details. Eremactis conara Bengtson & Conway Mor- ,. ris, sp. nov. (Figs 31-33)
Distribution. Lower Cambrian, South Austra lia. Fig. 30. Archiasterella hirundo Bengtson, sp. nov., Parara Lst., Curramulka, UNEL1848. All x50, except C, x150 and F, x250. A-C, SAMP30306. C, detail of B. D-F, holotype, SAMP30307. F, detail of E. G,H, SAMP30308.
58
STEFAN BENGTSON
et
al.
Etymology . Greek konaros, fat, well-fed; refer ring to the stout nature of the sclerite ray. Material. Holotype SAMP30310 (Fig. 31D-G), from the Ajax Lst. at UNEL1872, Mt. Scott Ra.; c. 20 paratypes. Distribution. Horse Gully, Parara Lst,� (UNE L1856); Mt. Scott Ra., Ajax Lst. (UNEL1872,' 1874).
the basal structures are not sufficiently distinct to show whether there are one or two foramina. One specimen (Fig. 33) shows a basal facet, 'suggest ing that it was adjacent originally to another sclerite, as in the rays of normal chancelloriid sclerites. Eremactis mawsoni Bengtson& Conway
Morris, sp. nov. (Figs 34-36)
.
.f
Diagnosis. Species of Eramactis having stout sclerites with basal facet usually perpendicular to long axis of ray. Two rays occasionally. fused in nearly parallel position. Description. Sclerites are stout single rays, up to c. 2mm long, with circular cross�section. Oc c'asional specimens are of two fused rays (Fig.32E,F). The length:width ratio varies from 4 to 6. The sc1erites may l?e cylindrical through most of their
length (Fig. 31D) or more spindle-shaped in profile (Figs 31A,H, 32A,C). They are straight or only slightly bent. The djstal end tapers to a point The proximal end forms a basal surface approximately perpendicular to the long axis of the ray. The· basal surface is delimited by a circular ridge forming a pronounced expansion of the proximal end (Figs 31A,B, 32D, 33E). This ridge is separated from the foraminal rim by a constric tion that often has a spherulitic surface (Figs 31F, 32B,H, 33E). The inner foraminal rim is circular and inay protrude considerably (Fig. 32G,H) or be almost flush with the outer ridge (Figs 31D-F, 32C,D). The rim usually has an uneven, lumpy appearance (Figs 31 F, 32D). Wi thin the foraminal rim the cavity is usually filled with matrix-like material. In some specimens there is a spherulitic texture, in particular on the inner surface of the rim (Fig. 31F,G). Specimens with partly broken base suggest that the internal cavity is funnel-shaped near the foramen, taper ing to a narrow canal at a distance of about O.lmm from the edge of the rim (Fig. 31B,E). The wall is consequently very thick. In partially phosphatized and broken specimens the wall ap pears to be built up of sheet-like elements radiat ing from the central canal (Fig. 31B,E,F) and oriented in the planes of radial symmetry of the sclerite (Fig. 31C). A longitudinal striation on the otherwise smooth outer surface (Fig. 31I) may relate to this inner structure, as worn specimens often show distinct longitudinal elements (Fig. 32D,H). Two specimens consist of double rays that have been fused along their length (Fig. 32E,F). The line of suture appears to go to the base, but
Etymology. After Sir Douglas Mawson, pioneer Australian geologist. Material. Holotype SAMP30327 (Fig. 36C,D) from the Ajax Lst. at UNEL1872, Mt. Scott Ra.; c. 60 paratypes. Distribution. Horse Gully, Kulpara and Parara Lsts (UNEL1857, 6429RS105, UNEL1856, 6429RSI0 7 , U N E L 1 8 5 4 , 64 29RS108, 6429RS109-110); Curramulka, Parara Lst. (UNEL1848, 1849, 1851); Mt. Scott Ra., Ajax Lst. (UNEL1865, 1866, 1869-1873). Diagnosis. Species of Eremactis having slender rod-shaped sclerites with basal facet almost parallel with the long axis of the rod. Description. Sclerites may be strikingly elon gate, but are invariably incomplete and lack the distal termination. Sides may be subparallel or may taper (Fig. 36E). In one specimen (Fig. 36G) the sclerite flares distally, but subsequently is incomplete. Probably the distal termination was conical Gudging fronl the condition in E. con ara). The sclerite can be divided into a short basal region and an elongate blade with a circular cross-section. The proximal base is set at an angle to the blade and is delimited by a distinct constriction that encircles the entire sclerite. The surface at the constriction has a fine spher ulitic texture (Fig. 34). The base bears a charac teristic ornamentation, of irregular longitudinal folds (Fig. 34). These extend onto the rim that encircles the apertural region, so giving the proximal termination a rather wrinkled and often nodular appearance. The elongate blade may be straight, or show a fairly pronounced curvature with the apertural· region facing the concave side (Fig. 36H,I). In well-preserved walls, the surface is smooth. However, the phosphatized wall often shows a linear ultrastructure, with fibres running parallel to the long axis of the sclerites (Fig. 361). These may be inherited from the original· calcareous skeleton, and weakly fibrous impressions on the steinkern surface may represent this same ultrastructure (Fig. 35A,B). In addition, the
.
EARLY CAMBRIAN FOSSILS, S. AUST.
59
Fig. 31. Eremactis conara Bengtson & Conway Morris, gen. et sp. novo Ajax Lst, Mt. Scott Ra., UNE L1872. All x50, except where otherwise indicated. B, stereo-pair. A-C, SAMP30309. B, detail of A, x200. C, detail of B, xlOOO. D-G, ho\otype, SAMP3031O. E, detail of D, x250. F, oblique view of base, x250. G, detail of F, xlOOO. H,I, SAMP30311. I, detail of H, x500.
60
STEFAN BENGTSON et al.
Fig. 32. Eremactis conara Bengtson & Conway Morris, gen. et sp. novo Ajax L st., Mt. Scot! Ra., UNEL1872. All x50, except where otherwise indicated. A,B, SAMP30312. B, detail ofA, x250. C,D, SAMP30313. D, detail ofC, x150. E, SAMP30314. F, SAMP30315. G,H, SAMP30316. H, detail ofG, x500.
EARLYCAMBRIAN FOSSILS, S. AUST.
61
Fig. 33. Eremactis conara Bengtson & Conway Morris, gen. et sp. nov.SAMP30317. Horse Gully, Parara Lst., UNEL1856. At! x75, except E which is a detail of D, x225.
stcinkcrn may bear irregularly spaced pillars, whose origin may be diagcnctic.
most layers, leaving the �pace between the outer and inner wall surface more or less empty. The walls are traversed by densely spaced tubules, c. 2-4n.tm wide and perpendicular to the surface
Structure and composition of chancelloriid sclerites[SBJ
(Fig. 37C,E). In phosphatized specimens, these arc usually preferentially impregnated (Figs 45A,B, 23H). The walls also contain longitudinal structural elements that may be visible on inter nal moulds (Fig. 26F), within imperfectly phos phatized walls (Fig. 24D), and on impregnated or encrusted outer surfaces (Fig. 23F). The lon gitudinal and nidial structures in Eremaclis are more sheet-like, but may have been modified from the structures present in the other chancel loriids. James & Klappa (1983) interpreted chanccl loriid sclerites as originally aragonitic; our evidence agrees well with that conclusion. In particular, recrys tallization of the walls is ub iquitous, even in rocks where originally calcitic skeletons (sponges, echinoderms, trilobites)
Chancclloriid sc1critcs arc usually preserved in the South Australian carbonate rocks as calcar eous walls enclosing a matrix-filled cavity. When the cavity-filling matrix is phosphatized (Fig. 37), acid-insoluble residues contain phos phatic moulds, either as isolated rays or as morc or less corn pletecom pos ite sclerites (Figs 26,27). In the latter case there is a distinct suture between the rays, representing the connecting wall. Inter nal moulds of rays oftcn stick together in etching rcsiducs because the dividing wall is only c. 1O-20f!.m thick (Fig. 37B,C,E). It may thus be come impregnated with phosphate or be pro tected from acid dissolution by the surrounding phosphatic moulds. The walls consist of calcite. The crystallo graphic structure is diagenetic, because it is made up of large, randomly oriented crystals, often in optical continuity with the surrounding calcite cement. This is in contrast to the preservation of calcareous sponges, echinoderms, and trilobites in the same rocks. These skeletal clements all retain the crystallography of the original calcite, in the sponges and echinoderms showing optical continuity of spicules and ossicles. In morestrongly phosphatized samples it is not uncommon to find chancelloriids with phos phatized walls (Figs 23-25, 29A-C, 30-32, 34). Usually the replacement involves only the outer-
have been preserved. The fibrous wall structure may represent phosphatic replacement or repli cation of fibrous aragonite. The spherulitic structure present in the basal regions of sclerites in C. racemifundis a n d Eremactis could conceivably have been formed diagcnctically b y apatite overgrowth on sur faces that were associated with decaying soft tissue. However, its consistent distribution on the sclerites, restriction to certain chancellori id taxa, and absence from other associated fossils make this interpretation implausible. We interpret this structure as secondarilyphosphatizedspherulitic aragonite, originally deposited in and around the sclerite base by living tissue.
62
STEFAN BENGTSON et al.
\
.....
.�
')jJ, .
Fig. 34. Eremactis mawsoni Bengtson & Conway Morris, sp. nov., Horse Gully, Parara Lst. (A, 6429RS]09; B-D, 6429RS107; E, 6429RS108). All xlOO. A, SAMP30318. B, SAMP30319. C, SAMP30320. D, SAMP30321. E, SAMP30322.
EARLY CAMBRIAN FOSSILS, S. AUST.
63
Fig. 35. Eremactis mawsoni Bengtson & Conway Morris, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1872. All xlOO. A,B, SAMP30323. C, SAMP30324. D, SAMP30325. Family SACHITIDAEMeshkova,1969
Etymology. Greek hippos, horse, and pharan gites, of a gully, for Horse Gully. The name is masculine in gender.
Genera inc luded. Sachites Meshkova,1969; Hippopharangites gen. novo
Type species. Hippopharangites dailyi sp. novo
Distribution. Siberian Platform, Australia; Lower Cambrian. Diagnosis. Coeloscleritophorans with elongate scleritcs of rounded cross-section and variable curvature. Basal portion more strongly curved so that basal surface forms angle with cross-sec tional plane of blade. Foramen small. Remarks. The Sachitidae resemble the Halk ieriidae in having a scleritome of scale- and spine-shaped sclerites, but the lack of articula tion facets and the variable morphology of the sclerites of the former suggest a less integrated skeleton, approaching that of the Chancellorii dae. Hippopharangites Bengtson, gen. nov.
Distribution. Australia, Lower Cambrian. Diagnosis. Sachitids having non-composite, elongated sclerites, usually asymmetrical, with round to oval cross-section, curving through 4590°, mostly near the base. Shape variation of sclerites considerable but apparently continuous. Foramen minute, situated subcentrally on a flat basal facet that due to the basal curvature forms an oblique angle with the long axis of the sclerite. Sclerite wall thin. Outer surface covered with imbricating scale-like tubercles. Inner surface with fine longitudinal striations. Hippopharangites dailyi Bengtson, sp. novo (Figs 38-40)
Etymology. In honour of the late Dr Brian Daily, eminent specialist on the Cambrian of Australia.
64
STEFAN BENGTSON et al.
Fig. 36. Eremactismawsoni Bengtson & Conway Morris, gen. et sp. nOv., Mt. Scott Ra., Ajax Lst., UNEL1872. All x50, except J. A,B, SAMP30326. C,D, holotype, SAMP30327. E, SAMP30328. F, SAMP30329. G, SAMP30330. H-J, SAMP30331. J, detail of I, x 1000.
EARL Y CAMBRIAN FOSSILS, S. AUST.
65
Fig. 37. Chancelloria sp. Horse Gully, Parara Lst., UNEL1856. Thin sections in plane-polarized light. A,B, SAMP30332. A, x50. B, detail of A, x200. C, SAMP30333, ,200. D,E, SAMP30334. D, x50. E, detail of D, x200.
Material. Holotype SAMP30340 from UNEL 1852, Parara Lst., Horse Gu lIy; c. 300 para types. Distribution. Horse Gully, Kulpara and Parara Lsts (UNEL1852-1854, 1856, 1857, 6429RS1 06·-113); Curramulka, Parara Lst. (UNEL 1845-1849, 1851); Kulpara, ?Parara Lsts (6529 RS104); Mt. Scot! Ra., Ajax Lst. (UNEL1867, 1869-1874). Diagnosis. As for the genus. Description. Sc1erites are elongate with an oval to round cross-section. Basal part of blade is at
45_900 to distal parts, most or all of the bend occurring in the proximal half of the blade. The basal facet is flat and subcircular with a small foramen near the centre. Sclerites are usually broadest at or near the base and taper gradually to a distal point. Asymmetry is produced by helical twisting of the blade. Variability. which appears to represent a mor phological continuum (Fig. 39) is evident in len gth:width ratio (2-·6), mode of tapering, shape of cross-section and basal facet, amount of curva ture and helical twisting. The most common mode of tapering involves a slowly increasing
66
STEF AN BENGTSON et al.
rate of taper toward the acute distal end starting at point past the midlength of the sclerite (Fig. 39Y). The base is often slightly narrower than the broadest part, rarely distinctly so (Fig. 38B). Some sclerites, however, are broadest at their base and taper uniformly distally (Fig. 391). In cross-section the main part of the blade varies from broadly round (Fig. 39I,J) to more or less narrowly ovate(Fig.39A,B), while thedistal end is more rounded. The cross-section of the proximal end more commonly approaches that of the main part of the blade, although here also it may become more rounded. Thus the shape of the basal facet varies from round (Fig. 39L) to ovate (Figs 39G, 40A), occasionally approach ing triangular (Fig. 401). In many specimens the basal foramen is indis tinct and may only be visible as a minute depres sion, about 1/10 the diameter of the basal facet (Fig. 40G,H). Internal moulds show it more clearly, as a funnel-shaped perforation in a some what thickened portion of the wall (Fig. 401,J). Its indistinctness in specimens with the wall preserved may be due to a thin encrustation of diagenetic apatite, but the possibility exists that the foramen was sealed during the last phases of sclerite formation. Basal and distal parts of the blade are at 45'90' (Fig. 39B,J) to each other. In some spec imens, particularly where curvature is sigmoidal, this angle may be less (Fig. 39F,X). Sclerites with simple curvature are only weak ly asymmetrical, and generally have an ovate basal facet with its long axis slightly inclined (Fig. 39C,Q). Left-handed and right-handed forms occur but many sclerites are nearly sym
Fig. 38. HipJX1pharangitesdail yi Bengtson, gen, et sp. novo Horse Gully, Parara Lst., UNEL1852. Holotype, SAMP30340. A-C, x80. D,E, details of C, x200.
metrical (Fig. 390). The surface is covered by densely set flattened tubercles inclined d i st a l l y (Fig. 39D,E). Proximally the tubercles are short and flat, reminiscent of imbricating scales (Fig. 39D). Distally, they become longer and more promi nent (Fig. 39E). The tubercles are generally pronounced on the upper side of the sclerite, but are smaller and more subdued on the lower sur face (Fig. 39B,K). The basal facet may be weakly pustulose (Fig. 40G). In sclerites with incompletely preserved walls, only the basal portions of the tubercles may be preserved, giving the wall a coarsely perforated appearance (Fig. 40A,D). In such specimens in ternal structures consisting of linear elements, c. 0.5-1.5f1m apart and parallel to the tubercles may be visible (Fig. 40B). The wall's inner sur-
Fig. 39. HipfX1pharangites dailyi Bengtson, gen. et sp. novo Horse Gully, Parara Lst., UNEL1852. All x50; A, C, and E stereo-pairs. A,B, SAMP30341. C,D, SAMP30342. E,F, SAMP30343. G,H, SAMP30344. I,J, SAMP30345. K,L, SAMP30346. M,N, SAMP30347. O,P, SAMP30348. Q,R, SAMP30349. S,T, SAMP30350. U,V, SAMP30351. W,X, SAMP30352. Y,Z, SAMP30353. Aa,Ab, SAMP30354.
EARLY CAMBRIAN FOSSILS, S. AUST.
67
68
STEFAN BENGTSON et al.
Fig. 40. Hippopharangites dailyi Bengtson, gen. et sp. nov., Horse Gully, Parara Lst., UNEL1852. A-C, SAMP30335. A, x80. B, detail of A, x 1000. C, detail of A, x500. D-F, SAMP30336. D, x 100. E, detail of D, x300. F, detail of E, x 1 200. G, SAMP30337, x 170. H, SAMP30338, x 170. 1,J, Stein kern, SAMP30339. 1, x170. l, detail of aperlural filling, x850.
EARLY CAMBRIAN FOSSILS, S. AUST.
face is generally smooth, but in several spec imens a weak longitudinal lineation is present (Fig.40C).
69
HALKIERIIDS [SCM]
Halkieriid sderites are common in Lower Cambrian skeletal assemblages (Bengtson & Specimens described here are phosphatized. Conway Morris,1984; Qian & Xiao,1984; Preservation is similar to that of other coelos Bengtson, 1985b; Duan, 1984; Qian & Zhang, c1eritophorans, and Hippopharangites is like 1983· Luo et ai., 1984; Qian & Yin, 1984a; Qian wise interpreted as originally calcareous. & B�ngtson,1989). Confusion has arisen be Remarks. One type of sclerite, here termed cause despite compelling evidence that the Hippopharangites c f. dailyi where it occurs scleritome housed several distinct types of . alone in a sample, may represent a dIfferent sclerite (Jell,1981; Bengtson & Missarzhevksy, species. This type is slender, and typically has 1981; Bengtson & Conway Morris, � 9 �), each � the strongest tuberculation in the proximal por with substantial morphological vanabIlIty, the tion. In some samples, fot example all those frox:n majority of workers appear to prefer form-taxa Curramulka in which the genus occurs, thIs to accommodate various elements of the scleri morph is the only one present. �owever, as t�e tome. While this bush of halkieriid taxonomy . usually contam sc1erite associations of H. dallYl needs pruning, reassessments are not strai�ht sequences gradational into slender sclerites forward. Most illustrations are not of a hIgh which are in practice indistinguishable from quality and may figure inc mplete scle�i�es; Lit ? . these forms, it is not possible to characteri�e a tle attention has been paId to vanabllIty, and new species on the basis o� the slend�r scJentes. differing modes of preservation .ha�e led to Landing (1988, pl.11, fIgs 7,8) fIgured two misinterpretation. Only a few prelImmary s sc1erites as Halkieria sp. from the Weymouth gestions regarding allocatl. n of s�me halkIerlld . �� ? Formation in eastern Massachusetts. Although sclerites to original sclentomes are therefore poorly preserved, they are similar to Hippopha possible. Realistic estimates of halkieriid diver rangites. sity cannot yet be made, but must be less than . existing literature indicates. Furthermore, With few scleritome reconstructions available, the Biology of Hippopharangites evolutionary history. of halkieriids remains clouded. Because structure and morphology of Hippo-. Terminology herein follows Bengtson & Con pharangites sclerites in many ways resemble way Morris (1984), aiming at distinction o� the those of halkieriids, they may have formed a major types of sclente . that mantled he vanous ! dorsal exoskeleton, similar to that of Halkieria zones of the body and documentatIOn of var (Bengtson & Conway Morris� 1� �4). Although iability within each type of sclerite. Articulated Hippopharangites sho�� vanabIl�ty ap�r�a�h materia] of a Middle Cambrian descendant, . ing that of other halkJerllds, there IS no dIvISIon Wiwaxia corrugata from the Burgess Shale; i of � into discrete sclerite types as in Halkieria and cardinal importance in scleritome reconstructIOn Thambetolepis. Sclerites of Hippopharangites (Bengtson & Conway Morris, 1984; Conway are basically spine-shaped, and no flat scales �re Morris, 1985). . . .. . present. However, the most common sclente Here, two Australian halklenld speCIes are type is semi-flatte?ed and has about th� same described, . confirming the major aspects of length:width ratIo as cul. trate s�lefJ!es of Bengtson & Conway Morris' (1984) reconst c . . ':! Halkieria. It would fIt well mto an Imbncatmg tion of Halkieria sp. from the lower TommotI�n exoskeleton, with the longer sclerites protruding of the Aldan River (Siberia), but also suggesting in the same way as in Wiwaxia and, by inference, modifications regarding sclerite distribution. Halkieria (Bengtson & Conway Morris, 1984). Halkieria parva sp. novo almost invariably co occurs with Thambetolepis delicata Jell, 1981, but is rarer. In both species palmate, cult rate and Hippopharangites is possibly a morphological siculate sc1erites are recognizable and are intermediate between the Halkieriidae and the believed to have originally mantled the dorsal, Chancelloriidae. The latter group also includes lateral and ventrolateral regions of the animal. forms with single rays (Eremactis) that in other Thus the locations of cultrate and palmate respects are identica� in structure to th� typi�al . scler{tes are transposed from the propo al by � multiple-rayed scJentes of Ch�nc�llorta. HlP Bengtson & Conway Morris (1984), hlle for w. popharangites represents a SImIlar type of the first time siculate sclerites are uneqUIvocally sc1erite; there is little to distinguish a slender identified in Lower Cambrian halkieriids. In T. sc1erite of this genus from a single-rayed chan delicata, moreover, a set of spinose sclerites may celloriid sclerite. .
.
70
STEFAN BENGTSON eta/.
EARLY CAMBRIAN FOSSILS, S. AUST.
71
be identified that are probably equivalent to the dorsolateral spines of W. corrugata.
species are clearly halkieriids; these include some elements assigned to S. proboscideus.
Family HALKIERIIDAE Poulsen, 1967
Halkieria Poulsen, 1967
Diagnosis. Bilaterally symmetrical metazoans with left and right calcareous sclerites disposed in several longitudinal zones. Principal types include blade-like palmate (?dorsal) and cultrate (?lateral) sclerites; siculate (?ventrolateral) and spiniform (?dorsolateral) sclerites in at least some species. Sclerite shape both within and between principal types l).ighly variable, with or without prominent base that houses foramen of restricted diameter. Surface ornamentation vari able; upper surface commonly bearing lon gitudinal ribs or tubercules and sometimes transverse ridges; lower surface usually with subdued transverse ribbing. Internally, central canal of widely variable width opening at proximal foramen. Lateral zones may comprise continuous longitudinal canals, but more usually divided into lateral canals or camerae. Lateral lacunae connected to central canal by minute pores.
1969
Taxonomic comparisons.Close relationship be tween the Halkieriidae Poulsen,1967, and Wiwaxiidae Walcott,1911, was discussed by Bengtson & Conway Morris (1984). Although often regarded as synonymous (Bengtson& Mis sarzhevsky,1981; Qian & Yin,1984a; Qian & Xiao,1984), they are treated here as separate. The Wiwaxiidae contains only Wiwaxia corrugata (Matthew,1899;Conway Morris, 1985;Conway Morris & Robison, 1988), and is distinguished from the Halkieriidae by sclerites that are larger, unmineralized, and form a less tightly integrated scleritome. Genera presently placed within the Hal kieriidae include Halkieria Poulsen,1967, Sino sachites He in Yin et al., He,1981, Microsachites He,1981, and Thambe tolepis Jell,1981 [with regard to Sachitelus see Bengtson& Conway Morris,1984, p.308]. The status of the type species of Sachites (S.pro boscideus Meshkova,1969) is dicussed above. This species appears to lack the int�grated halkieriid scleritome, but most of the remaining
Sachites Meshkova, p.165. (partim) [non S. proboscideus Meshkova, p. 165].
*?1979 Tianzhushania Qian, Chen & Chen, p.217 *?1981 Dactyosachites He, p. 86.?1982 AethesachitesQian in Gao et al., p. 525. [nomen nudum]
?*1984aAcuminachitesQian & Yin p.105 (?partim) [?non A. elongus Qian & Yin]
*1984 Acrosquama Qian & Xiao, p. 72. ?1984 Sachithes [sic] Fedorov,p.7.
Type species. Halkieria obliqua Poulsen, 1967 from the Early Cam.brian of Bornholm; by original designation. Other species. ?H. belIa (Qian in Gao et a l ,1982) [nomen nudum]; H. mira (Qian& Xiao, 1984); ?H.lata (Qian& Yin,1984a) (?in part);H. cur vativa Mambetov in Missarzhevsky & MariI� betov, 1981; H.denlanatiformis Mambetov in Missarzhevksy & Mambetov , 1981 (specific name misspelt denlataniformis onp;65);H.tri anguliformis Mambetov in Missarzhevsky' & Mambetov,1981; H. alata (Duan,1984);H. amorphe (Meshkova,1974a); H. asymmetrica (Mo s t l er, 1 9 8 0 ) ; H. c o s t u l a t a ( M e s h kova,1974a); H.desquamata (Duan, 1984);H. folIiformis (Du an, 1984);H. hexagona (Mostlet, 1980); H.lata (Mostler, 1980);H: longa (Qian, 1977); H. longispinos (Most ler, 1 980); H. maidipingensis (Qian, 1977);H.mina Qian et al.', 1979;H.operculus (Qian, 1984);H.praeinguis (Jiang in Luo et al., Yin, 1984a);H.sacciformis (Meshkova, 1969); H. solida (Mostler, 1980);H. sthenobasis (Jiang in Luo et al., 1979); H. uncostata (Qian & Yin, 1984a);H. ventriosa (Mostler, 1980); H.zapfei (Mostler, 1980);?H.meshkovae Fedorov, 1984;?H. longa Qian et al., .
_
Distribution.Lower Cambrian, principally and possibly exclusively Tommotian and Atdabani an, of Siberia, Kazakhstan, Mongolia, China,
Fig. 41. Halkieria parva Conway Morris,sp. nov., palmate sclerites. Curramulka, Parara Lst.; UNEL1846 (A I); Horse Gul1y,Parara Lst.,UNEL1852 (J-Z). A-F, SAMP30355. A, upper view, x35. B, lateral view, x60. C, lateral view, x50. D, upper surface, x135. E, ornamentation, x300. F, margin of upper surface, x325. 'G-I, SAMP30356. G, lower view, x40. H, oblique view, x40. I, distal view, x65. J�M, holotype, SAMP30357. J, distal view,x65. K, lower view,x40. L, lateral view,x55. M, lateral view, x50. N-R,SAMP30358. N, lower view, x35. 0, distal view,x45. P, lateral view,x60. Q, lateral view,x40. R, proximal view of base, x100. S-U, SAMP30359. S,lateral view,x30. T, distal view,x40. U, lower view, x25. V, SAMP30360, lower view, x35. W, SAMP30361, distal view, x50. X-Z, SAMP30362. X, lateral view, x25. Y, upper view, x25. Z, proximal ' view, x55.
11
S11ZFAN DIlNOTSON,," .
EARLY CAMBRIAN FOSSILS, S. AUST.
73
Pakistan, Bornholm, England, France, southeast diping area, Sichuan (Qian, 1977; He in Yin et Newfoundland, M assac h u setts, A u stralia, ai., 1980). (Bengtson & Conway Morris,1984; fig.1), and Antarctica (Gazdzicki & "Wrona,1986). Halkieria parva Conway Morris sp. nov. (Figs , 41-48) Diagnosis. Cultrate and palmat e sclerites, probably also siculates. Broad central canal Etymology. Latin parvus, small. flanked on superior and inferior edges by narrow longitudinal canals, sometimes divided into Material. Holotype SAMP3035 7 (palmate camerae by longitudinal and transverse parti sclerite; Fig. 411-M) from UNEL1852, Horse Gully, Parara Lst. Paratype suite of palmate tions. Upper surface frequently ribbed with tubercles or other ornamentation. (SAMP30358-30372), and cultrate (SAM P30377, 30378) sclerites from UNEL1852. Comparisons. The type species is known only DistriblJ,tion. Curramulka (UNEL1845-1848, from cultrate sclerites (Bengtson, 1985b) so the possibility remains that its scleritome was dis 1851), Horse Gully (UNEL1852-1856), and Kulpara (UNELI860B, 1860C), Parara Lst. ; tinct from other species that are now placed in Horse Gully, Kulpara Lst. (UNEL1857); Mt. Halkieria. Acrosquama mira from the Aksu-Wushi area Scott Ra., Ajax Lst. (UNEL1874, 1877). of Xinjiang (Qian & Xiao, 1984) has recog Diagnosis. Species of Halkieria with three (pos nizable palmate and cultrate sclerites. Aethe sachites bellus [nomen nudum] from the same sibly four) highly variable sclerite types occur area (Gao et al., 1982) may also refer to this ring as left-and right-hand forms. Palmate sc1erites (?dorsal) with compressed blade, taper species. One specimen of Acuminachites latus (Qian & Yin, 1984a, pt. 3, fig. 5a,5b) has a ing to a point, generally narrow but occasional1y halkieriid-like orn amentation (cf. Bengtson & triangular, asymmetrical. Base prominent, usual Conway Morris, 1984, fig. 6D-F). However, ly at steep angle to blade. Cultrate sderites (?lateral) with compressed and tran,sversely other material assigned to this species and A. strongly curved bl�de, slight asymmetry. Base elongus (Qian & Yin, 1984a, p1.3, figs 3,4; pl.3, moderately prominent, occasionally subdued. In figs 2,6, respectively) is not readily identifiable. Dactyosachites He, 1981 (D. pennatus) and all sclerites broad central canal, flanked by long itudinal canals with subcircular tranSverse sec,: Tianzhushania Qian et ai., 1979 (T. longa and T. obesa) are tentatively assigned to Halkieria. tion, extermllly often delimited from central canal by furrows. Upper side with ornamentation Some species o f Halkieria are probably of transverse and longitudinal ribbipg, giving tessellate pattern; lower side with subdued synonymous and represent the variously shaped sclerites derived from a single scleritome. Pub transverse ridges. Rare siculate sc1erites (?ventrolateral), elongate blade with- quadrate lished data are usually insufficient to test this, however. It also seems questionable whether cross-section, merging with slender base. Pos� various assignments to certain taxa, as defined sible spinose sclerites elongate, with curved blade joining base with wide, terminal foramen. by their type suite, are correct. The following species are conceivably synonymous: H. asym metrica, H. cf. costulata, H. hexagona, H. lata, Description. Preservation of sclerites is broaqly comparable to that noted in Thambetolepis (see H. longispinosa, H. sacci/ormis, H. solida, H. ventriosa and H. zap/ei from Pakistan (Mostler, below). Phosphatization of the originally cal careous wall is variable, but complete replace 1980, all specimens from same horiion); H. /01ment is unusual. In many specimens little or none li/ormis, H. desquamata and H. alata irom Shen nongia district of Hubei (Duan, 1984); H. of the wall has been phosphatized and the inter sacci/ormis, H. costulata, H. maidipingensis, H. nal canals (central and longitudinal) are repre� sented as phosphatic steinkerns (Figs 411amorphe and H. longa (Qian,1977) from Mai.
Fig. 42. Halkieria parva Conway Morris, sp. nov., palmate sc1erites. Horse Gully, Parara Lst., UNEL1852. A F, SAMP30363. A, lower view, x35. B, distal view, x70. C, steinkern surface with connecting pores and possible
endolithic borings, x600. D, longitudinal canal and lateral edge of central canal, x325. E, lateral view, x40. F, lateral view, x40. G-J, SAMP30364. G, lateral view, x50. H, lower view, x35. I, distal view, x80. J, lateral view, x40. K-M, SAMP30365. K, lower view, x45. L, lateral view of base, x215. M, lateral view, x35. N-Q, SAMP30366. N, lower view, x40. 0, oblique view, x60. P, oblique view of proximal region, x80. Q, longitudinal canal and base, x250. R-W, SAMP30367. R, lateral region, x250. S, lower view, x55.- T, proximal view, x60. U, oblique view, x55. V, distal view, x65. W, lateral view, x70.
74
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AVST.
Z,42A-G). In such instances, the longitudinal canals are seldom preserved complete and may be partially or completely absent along .one or both sides. These steinkerns are usually phos phatic linings that incompletely fill the original cavity. In contrast, steinkerns of the central canal and basal region are usually more massive, al though infill of phosphate is often only partial. Connecting pores between the central and lon gitudinal canals may be similarly filled. In contrast to Thambetolepis, where incom plete fragments of blade, base or central canal are often assignable to one of the four sclerite types, inH. parva palmate and �ultrate sclerites usually must have the base preserved for reliable iden tification. Notwithstanding the relative abun dance of indeterminate fragments, palmate sclerites seem to be about twice as abundant as cultrates. Siculate sclerites are much rarer, and they are also difficult to separate from putative spinifotms. Palmate and cultrate sclerites usually have a narrow blade, set at a variable angle to the base. Much of the blade was occupied by the central canal that opened via the basal foramen and extended to the distal tip. The foramen is often obscured, but it was narrow (Fig. 42L). On either side of the central canal there was a longitudinal canal (so termed to avoid confusion with the homologous lateral canals in Thambetolepis), arising from the basal area (Fig. 42A,B,F) and extending along the superior and inferior mar gins of the blade to meet about the distal mid point (Fig. 44G,H), although apparently without direct connection. In cross-section the lon gitudinal canals are sub-circular (Figs 41 D,Q,R, 45H). The central and longitudinal canals are closely juxtaposed, but where the dividing wall is unusually thick, connecting pores (Figs 43C E, U, 48K,L) are densely spaced and flare, abaxially (diameter increasing from 2.5�m to 12.5�m). In other sclerites truncated proximal sections of the steinkern fillings remain attached to the central canal. The steinkerns of the con necting pores are annulate. Perhaps diagenetic, this structure is thought more likely to reflect the microstructure of the surrounding wall on ac count of striking similarities to the primary layer
75
of some articulate brachiopods (Alvarez et al., 1985, fig.2b) and more particularly limonite filled endoliths in fossil shells (Gatrall & Golubic, 1970, p1.3, fig. 3c,e). Palmate sclerites (Figs 41-43, 44T, 46F-J, M P). The elongate, asymmetrical blade has gently convex margins tapering to a distal point (Figs 41K,N,Y, 42A,H,K, 46M). In contrast to the cultrates, blade curvature about its transverse axis is usually slight. The base is often pro minent, its long axis oblique to the rest of the sclerite and one end extending as a prominent auricle (Figs 411,J,K,W,Y,Z, 42A,H,I, K,N,S, 43A,B, 461,M,O). Along the distal side there is a pronounced change in slope: on the inferior side the lower surface of the blade rises without inter ruption to the base, whereas towards the superior side the base is abruptly angled and is typically obtuse to the blade.' Consequently the distal profile of the base is triangular (Figs 41J,W, 421). The proximal side of the base connects to the upper surface of the blade by a zone of con tinuous curvature, and often has a concave profile (Figs 41G,H,M,R, 42E,G,T,W, 46H,J) that appears to represent a facet for interlocking with an adjacent sclerite. The apertural area housing the foramen is typi cally transversely elongate and located towards the inferior end of the base, i.e. opposite the auricle (Figs 41J,W, 46M-O). Whether this,elon gate slit corresponds to the foramen or a sur rounding depression is uncertain, hut in some specimens the foramen consists of a narrow channel (Fig. 42L) ten times narrower than the . blade. Cultrate. sclerites (Figs 44A-S, 45, 46A-E, K,L). The elongate blade exhibits gentle curva- . ture about its longitudinal axis (Fig. 44L,R), with subparallel margins and blunt tip (Fig. 46B-D). The base lies more or less at right angles to the longitudinal axis of the blade, rising steeply in a smooth curve (Figs 44A,C, 45A,E). The aper tural region occupies most of the crest (Figs 44A,I,M-Q, 45F), consisting of elongate ridges around a slit-like foramen (Fig. 46K,L). Siculate and spiniform sclerites (Fig. 47). Iden tification of siculates is complicated by low num bers and the possibility that such sclerites are a
Fig. 43. Halkieria parva Conway Morris, sp. nov., palmate sc1erites. Horse Gully, Parara Lst., UNEL1852 (A
N), UNEL1854 (O-Q), UNEL1856 (R-V). A-E, SAMP30368. A, lower view, x40. B, oblique view, x50. C, distal view of connecting pores, x165. D, connecting pores, x400. E, oblique view of connecting pores, x300. F- I, SAMP30369. F, distal view, x30. G, oblique view, x20. H, lateral view of base, x80. I, lower view, x20. J-L, SAMP30370. J, oblique view, x60. K, upper view, x35. L, lateral view, x40. M, SAMP30371, upper view, x50. N, SAMP30372, upper view, x45. O-Q, SAMP30373. 0, proximal view, xl10. P, upper view, x55. Q, lateral view, x75. R, SAMP30374, lower view, x55. S-U, SAMP30375. S, lower view, x50. T, proximal view, x75. V, proximal end with longitudinal canal, connecting pores and steinkern of central canal and basal region, x150.
76
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
77
Fig. 45. Halkieriaparva Conway Morris, sp. nov., cultrate sclerites. Horse Gully, Parara Lst., UNEL1856 (A D,I), UNEL1854 (E-H). A-D, SAMP30381. A, lower view, x55. B, distal view, x75. C, lateral view, x60. D, lateral view of base, x280. E-H, SAMP30382. E, distal view, x75. P, lower view, x60. G, lateral view, x80. H, longitudinal canal, x275. I, SAMP30383, lower view, x40.
variant of the cult rates. Putative siculates (Fig. 47A-N,Q,T)are simiIartothe cultrates in having elongate blades with subparallel sides and transversely a pronounced curvature. They differ in being more slender and having a subcircular base. The apertural region is delimited by ridges (Fig. 47E,F), prominent on the distal side. The foramen is not clearly preserved, but may have been restricted. Identification of spiniform sclerites (Fig. 47 Q,P) is more tentative. Possible examples have an elongate blade, quadrate to subtriangular in cross-section. The central canal occupied much of the blade, so the longitudinal canals were reduced or absent. The base is at low angle to the blade. It has a wide apertural region that may
have embraced a correspondingly broad for amen. HaIkieria sp. A (Fig. 49)
Material. SAMP30406-3041O from the Wang konda Lst. at the Sellick Hill section, on Main South Road, Fleurieu Peninsula. Description. The phosphatic steinkerns are in variably incomplete making assignment to sc1erite types difficult Possible cultrate sclerites (Fig. 49A,C,D,?E) are transversely curved, the upper surface bearing a prominent longitudinal ridge. A general outline of the base is apparent, but the distal termination is invariably absent
Fig. 44. HaIkieriaparva Conway Morris, sp. nov., cultrate (A-S) and palmate ( T ) sclerites. Curramulka, Parara Lst., UNELl846 (A, B); Horse Gully, Parara Lst., UNEL 1852 (C-P,T), UNEL l856(Q-S). A,B, SAMP30376, stein kern. A, lower view, x135. B, lateral view, x120. C-H, SAMP30377. C, oblique view of lower surface, x50. D, detail of proximal region, x135. E, lower view, x40. P, base, x165. G, distal termination, x150. H, distal region, x135. I-P, SAMP30378. I, lower view, x65. J, oblique view, x75. K, oblique view, x45. L, lateral view, x75. M, oblique view of proximal region, x120. N, lower view of proximal region, x 110.0, lower view, x45. P, lateral view of base, x215. Q-S, SAMP30379. Q, lower view, x75. R, lateral view, x50. S, proximal view of base, x.l50. T, SAMP30380, lower view, x30.
78
STEFAN BENGTSON et al.
'
The other sclerite type has a subquadrate cross section, but the basal region is absent. They may represent either siculate or spiniform sclerites (Fig. 47). Palmate sclerites have not been recog nized. Possible imprints of shell ultrastructure occur on the steinkern surface of some ?cultrate sclerites (Fig. 49B). Consisting of longitmjinal striations, they recall the more subdued struc tures on the homologous central canal of T. delicata (Figs 57J, 62F). Discussion. These sclerites differ from the younger H. parva, in size and the prominent median ridge on the upper surface of the ?cuHrate sclerites.
Thambetolepis Jell, 1981
Type and only species. T. delicata Jell, 1981, Early Cambrian from Ardrossan. Distribution. Lower Cambrian of Australia (South Australia, Northern Territory). Diagnosis (modified from Jell, 1981, p.88). Cultrate, palinate, siculate and ?spiniform scler ites present. Centra] canal flanked on inferior and superior sides by series of lateral canals.
Thambetolepis delicata Jell, 1981 (Figs 50- 62)
Material. Holotype NMVP61743. Paratypes NMVP61735-61742, 61744-61752 (Horse Gully, probably 1-25 m above base of the Parara Lst., Jell,1980,1981); several hundred further sclerites were collected during this project. Distribution. UNEL1845-1849, 1851-1853, 1856, 1857, 1860, 1862B, 1866-1869, 18701874, 1877, NMVPL95, Horse Gully, Kulpara, Curramulka, and Mt. Scott Ra., Parara Lst; Ross River Gorge, Todd River Dolomite. Diagnosis. S p e c i e s o f Thambetolepis w i t h probably four sclerite types, each occurring as left- and right-hand forms. Variation within each sclerite type pronounced. Palmate sclerites (?dorsal) with subtriangular strongly com pressed blades with limited transverse curvature, asymmetrical. Cultrate sclerites (?lateral) with elongate transversely curved and compressed blades, asymmetry usually slight but occasional ly pronounced. In cultrates and palmates transi tional series between sclerites with prominent base set at steep angle to blade to those with subdued or recessed bases. Siculate sclerites (?ventrolateral) elongate with base at steep angle to blade, cross-section of blade subcircular to qua drate, base sometimes with prominent flange(s). Spiniform sclerites (?dorsolateral) elongate with quadrate cross-section, base at less steep angle to blade than in siculates.
Comparisons. Similar halkieriid sclerites with a prominent array of lateral canals are known from Sichuan as Sinosachites flabelliformis (He in Preservation. Mostly preserved as opa que brownish phosphate. Ajax Lst. specimens may Yin et a!., 1980, pl.l8, fig.3; He, 1981, text-fig.6, pl.1, fig.6; note that it is not clear whether these show replacement by translucent white phos canals are present in material from Yunnan phate with additional silica(?), or rarely glau ascribed- to this species by Jiang (in Luo et al., conite. Phosphatization is post-mortem and 1982, 1984», S. triangularis He (in Yin et Aiagenetic, but concerning original sclerite com al.,1980; He,1981,-pl.l, figs 1,2; as above Jiang's , osition there has been a divergence of opinion. (in Luo et a!.,1982, 1984) identification of S. Jell (1981) espoused an organic composition that was effectively unmineralized, whereas Beng triangularis from Yunnan is regarded as ques tionable), Microsach ites phylloideus (He, 1981, tson & Conway Morris (1984) argued that the sclerites were composed originally of calcium ' text-fig.8, pl.1, fig.8), and apparently Dac tyosachites pennatus (He, 1981 , text-fig.7). The carbonate. Further support for this notion is as follows. se sclerites appear to be rather worn. It is not Thin-sections of Thambetolepis show that the known if they could be derived from a common , walls may be composed of coarsely crystalline scleritome.
�
Fig. 46. Halkieriaparva Conway Morris, sp. nov., cultrate (A-E,K, L) and palmate (F-J, M-P) sclerites. Horse
Gully, Parara Lst., UNEL1853 (A-J, M-P); Curramulka, Parara Lst., UNEL1763a (K,L). A, SAMP30384, lower view, x50. B, SAMP30385, upper view, x50. C-E, SAMP30386. C, lateral view, x50. D, lower view, x50. E, distal view, x50. F,G, SAMP30387. F, upper view, x95. G, lateral view, x95. H-J, SAMP30388� H, lateral view, x55. I, distal view, x90. J, lower view, x95. K,L, SAMP30389. K, basal region, x185. L, lower view, x45. M-O, SAMP30390. M, distal view, x95. N, lower view, x45. 0, lower view of basal region, x180. P, SAMP30391, lower view, x45.
EARLY CAMBRIAN FOSSILS, S. AUST.
79
80
STEFAN BE NGTSON etal.
Fig. 47.
parva Conway Morris, sp. nov., siculate (A-N,
Q-T)
and possible spiniform (O,P) sc1erites.
Curramulka, Parara Lst., UNEL18SI (A-G), UNEL1 846 (M, N); Horse Gully, Parara Lst., UNEL18S4 (H-L), UNEL18S6 (O-T). A-D, SAMP30392. A, lateral view, xSS. B, lateral view, xSS. C, oblique proximal view, x60. D, lower view, xSO. E-G, SAMP30393. E, lower view, xSO. F, proximal view, x7S. G, lateral view, xSO. H-J, SAMP30394. H, lateral view, x7S. I, proximal view, x lOO. J, oblique distal view, x100. K,L, SAMP3039S. K, oblique upper view, x60. L, lateral view, x3S. M,N, SAMP30396. M, distal view, x7S. N, upper view, x40.. O,P, SAMP30397. 0, lower view, x4S. P, proximal view, x80. Q-T, SAMP30398. Q, lateral view, xSO. R, upper view, xSS. S, proximal view, x !OS.
T,
distal view, x80.
EARLY CAMBRIAN FOSSILS, S. AUST.
calcite (ct. Bengtson & Conway Morris, 1984, fig.9A,B), but the carbonate that occludes the internal spaces defined by the canal system and basal cavity is obviously diagenetic. Replication of shell microstructures on the steinkern surfaces (see below) is also consistent with the walls being originally calcareous. Secondary phos phatization is, however, widespread but seldom entails complete replacement. Internal cavities are typically lined or partially filled to produce phosphatic steinkerns. Part or all of the outer wall may be phosphatized. The most frequent occurrence of Thambeto le pis is as steinkems of the basal region, central canal (Fig. 51F), and lateral canals (Figs 50A, 52A, 54A,C,0, 55L, 570-T, 62C,D), although replacement of the distal extremities of the latter may be incomplete. Usually steinkerns of the lateral canals provide faithful replicas, consisting of an inner phosphatic coating that leaves a central lumen (Figs 5 5K, 62K; Jell, 1981, fig.2B). However, blocky phosphatization may obliterate a tract oflateral canals (Fig.62E), espe cially in palmate sclerites where proximal lateral canals, adjacent to the base, may be obscured (Figs 50B,C, 51H). Phosphatization of the outer wall is, with the exception of siculate sclerites, rather infrequent and may be patchy. Where present, however, the ornamentation is often well preserved (Figs 50I-L, 511,0, 53F,K). The extent of phosphatization governs our ability to reconstruct sclerite morphology. Rela tively subtle details of the base and apertural region rely on exceptional preservation. Large specimens are usually represented by steinkerns of the central canal so a bias towards juveniles is probable in our samples. Style of preservation varies at different horizons, with the extent of phosphatization presumably control led by diagenetic conditions dependent on varying micro-environments and perhaps mi crobial capacities. Elucidation of these taphonomic fac tors will lead to better appreciation of preserva tional bias. No internal fabric has been preserved in the coarsely crystalline calcareous walls, because of extensive recrystallization. An indication of the shell microstructure of the inner wall is ob tainable, however, from impressions on phos phatic steinkerns (cf. Runnegar & Bentley, 1983; Runnegar, 198 5b; Conway Morris & Chen, 1989), especially on the bases of sclerites and central or lateral canals. Shell microstructure proximally on the cultrate base consists of sub parallel fibres (Fig.54Q), medially adopting a fan-like pattern (Fig.54M) that overlaps along the midline and diverges towards the apertural region. Superimposed on this microstructure are widely spaced lines running at right angles to the
81
fibrosity (Fig. 54N). On the distal side of the basal region, best seen in pal mates, the shell microstructure consists of acicular bundles that diverge towards the aperture (Figs 50H,51B). Shell microstructure on both the inner and outer surfaces of the canal walls is also present. Along the stein kern of the central canal (Fig. 62F), including the recurved section that ran through the base, a subdued fibrosity runs paral lel to the long axis of the canal. Where the central canal passes through the sclerite base the sur rounding steinkern replicates its outer surface. Their microstructure is also fibrous (equivalent to the 'fine textures' of Jell (1981, fig.6G», suggesting a homogenous shell structure of the canal wall. Steinkerns of the upper and lower surfaces of lateral canals reveal little apart from a vague fibrosity. However, replication of microstructure of the inner surfaces of walls separating adjacent lateral canals displays obli quely inclined bundles radiating abaxially about a median division (Fig. 62G,H). The fibrous ul trastructure seen on the steinkern surfaces seems to be consistent with an originally aragonitic composition, as deduced for the chan celloriids. Description. The overall similarity of the scler ites with central canal, lateral canals and basal cavity, all enveloped by an outer wall, has been discussed by Jell (1981). His small sample from the Parara Lst., however, precluded confident recogni tion of recurrent e l ements of the scleritome. The shape o f the central canal varies according to the sclerite type, but otherwise it maintains roughly the same proportions. Thus it occupies much of a narrow siculate, but relative ly little of broader cultrates and palmates (cf. Figs 50A, 54A with 570,T, 59A,S). The central canal usually tapers at a relatively even rate, but occasionally the distal area is defined by a pronounced constriction. Much of the thickness of the sclerite is occupied by the central canal (Jell,1981). Thin-section examination confirms that the calcareous wall of the canal was con fluent with upper and lower" sides of the outer wall. In most halkieriids the central canal occupies much of the blade, so that the l ateral zones hous ing the longitudinal canals (sometimes camerate) are restricted. Such pertains to siculate and spiniform sclerites of Thambetolepis, but this relationship is reversed in the broader cultrates and palmates so that the homologous lateral canals occupy a substantial width. Lateral canals arise from the central canal, and are connected by fine pores (see below), except that in cultrates and palmates expansion of the base means that the proximal lateral canals connect to the basal
82
STE"AN 8E1'ClTSON .. .I.
EARLY CAMBRIAN FOSSILS, S. AUST.
cavity rather than the central canal (Figs 51E, 540, 551,J,L). Width of lateral canals is fairly constant, apart from tapering to an abaxial termination. Typical ly lateral canals are inc1ined distally, any pronounced curvature confined to extremities. Occasionally lateral canals show stronger curva ture or even angular bends (Fig. 62C,D; Jell, 1981, fig.2A). The margins of adjacent lateral canals are usually slightly sinuous (Fig.62J,K), presumably reflecting the somewhat irregular thickness of the narrow intervening walls. Lateral canals occupy the bulk of a sc1erite's thickness and run without branching from the central canal (or base) to the margins, although occasionally a canal is pinched out on either the upper or lower surface so as to be cradled by the adjacent canals (Fig.62A). In transverse section the lateral canals are quadrate (Figs 55K, 62I,N; Jell, 1981, fig.2B), but unlike the homologous zones of other halkieriids a transverse partition appears to be absent. However, microstructural replication of a median line on the walls of the lateral canals conceivably represents an un mineralized division. Jell (1981) found no indication for a connec tion between the lateral and central canals. In accepting this observation, Bengtson & Conway Morris (1984) used it as one argument against fluid circulation within the sc1erites for such functions as respiration or digestion. However, unequivocal evidence for connections exist in the form of narrow canals (Fig. 52A-C,F). These connecting pores, with circular cross-section and apparently constant diameter, are most obvious where the original calcareous wall separating central from abutting lateral canals was abnor mally thick, so promoting infill by phosphate. However, they are also recognizable on stein kerns of the central and lateral canals (Fig. 62B,L). Although not observed, it is· probable that the junction between proximal lateral canals and basal cavity in cultrates and palmates was also perforated. Canals connecting adjacent lateral canals have not been observed. In some sclerites the calcareous wall was ab normally thick, judging from the pronounced separation between lateral canals and the outer . phosphatized surface. This gap houses fine tubules, now occupied with diagenetic phos-
83
phate (Figs 52D,E, 550,P), but possibly origi nally fluid or tissue-filled extensions of the canal system forming a punctae-like structure within the calcareous wall. An endolithic origin seems less likely. These tubules appear to have been blind rather than opening to the sc1erite surface. Palmate sc1erites (Figs 50,51,152). The extent of diagenetic phosphatization is variable. The basal cavity and central canal are most common ly preserved, the lateral canals less often and the outer wall least frequently replaced. An excep tion occurs in specimens with a recessed base (see below), where the outer wall is often intact, perhaps because the sclerites are generally smaller. The outline is typically subtriangular, with slight asymmetry (Figs 50A,C,F,G,J, 51K,L,P). In transverse section the blade is strongly com pressed (Fig. 51N) and is usually gently folded about the transverse axis, with the upper side convex. The upper surface of the blade is variab ly ornamented. Some sc1erites have prominent longitudinal ridges (c. 12) that converge distally, but die out before the tip. These ridges may bear blunt tubercles (Fig. 50L), inclined distally. Al though their spacing along any ridge is fairly even (c. 25/mm), no regular pattern forms across the blade. Adjacent to the base the tubercles grade into a rather narrow zone of transverse ridges (Fig.50K). In other palmates a transverse ornamentation occupies almost the entire upper surface (Fig.51 I). On the lower surface of the blade, ornamentation is more subdued as fine transverse crenulations (Fig.50I), although on occasion more prominent transverse ribs (3-4) occur (Fig. 51 L-O). Variation is most clearly expressed in the base. The basal cavity is usually preserved as a more or less complete steinkern, but the thinness of the original wall means that it provides a reliable guide. As viewed from the lower side, a wel� developed base (Figs 50B,C,N, 51E-H) is asym metrical, crudely lenticular and tapering in the same direction as the gentle curvature of the central canal. The proximal side (Figs 50M,51D) may be subvertical or more gently sloping, grad ing into the upper surface of the blade without obvious interruption. In contrast, the distal side is often recessed with an overhanging rim along its free margin (Figs 50A,F, 51C,D). The lower
Fig; 48. Halkieria parva Conway Morris, sp. novo Curramulka, Parara Lst., UNEL1846 (A-E), UNEL1848 (F I); Horse Gully, Parara Lst., UNEL1856 (J-O), UNEL1854 (P,Q). A-E, SAMP30399. A, upper view, x40. B, proximal view, x150. C,D, ornamentation of upper surface, x195 and x215. E, lateral ornamentation, x400. F,G, SAMP30401. F, upper view, x40. G, ornamentation, x250. H,I, SAMP30402. H, upper view, x50. I, lateral view, x50. J-L, SAMP30403. J, distal view, x35. K, connecting pores arising from central canal, x450. L, connecting pores, x275. M-O, SAMP30404. M, upper view, x35. N, lateral view, x35� 0, ornamentation on proximal part of upper surface, x215. p',Q, SAMP30405. P, lower view, x120. Q, proximal view, x185.
84
STEFAN BENGTSON et al.
Fig. 49. Halkieria sp. Sellick Hill, Wangkonda Lst., Cooper Collection, Sample 6(A-H), Sample 9 (C-T). A,B, SAMP30406, steinkernofc ultrate sclerite. A, lower view, x75. B, surface showing possible shell ultrastructure, x360. C,D, SAMP30407, c ultrate sclerite. C, upper view, x190. D, lateral view, x180. E, SAMP30408, lower view of?c ultrate sclerite, x345. F,G, SAMP30409, ?siculate sclerite. F, lateral view, x230. G, lower view, x290. H,I, SAMP30410, ?siculate sclerite. H, lateral view, x290. T, oblique view, x375.
Fig. 50. Thambetolepis delicata Jell, 1981, palmate sclerites. C urramulka, Parara Lst., UNEL1763a. A, SAMP30411, lower view, x65. B, SAMP30412, lower view, x45. C, SAMP30413, lower view, x45. D,E, SAMP30414. D, lower view, x45. E, inner surface of base, x675. F,M, SAMP30415. F, lower view, x45. M, oblique view o f lower side, x45. G-T, SAMP30416. G, lower view, x45. H, inner surface of base, x 170. T, ornamentation on lower surface, x680. J-L, SAMP30417. J, upper view, x45. K, ornamentation near proximal end of upper surface, x 170. L, ornamentation on upper surface, x 170. N, SAMP30418, lower view, x45.
EARL Y CAMBRIAN FOSSILS, S. AUST.
85
86
STEFAN BENGTSON et al.
surface of the base is rdatively narrow and houses the foramen either subcentrally or slight ly towards the wider (Le. superior) end of the base. The foramen is usually suboval, parallel to the long axis of the base (Figs 50A-D, G,N, 51A,E,H,J). A gradational series exists between sclerites with a prominent base, to those subdued in ex pression, to an end-member where the basal region .is either flush with the blade or even recessed (Fig.51L,M,P). This last type tends to be relatively small, and may be more character istic of juveniles. However, variable develop ment of the basal region is unlikely to be simply ontogenetic, as larger sclerites with relatively subdued basal regions are known. The possibility that basal developm�nt is a reflection of location within the scleritome is discussed below. The central canal shows a gentle curvature that reflects the moderate asymmetry of the blade. The proximal section, housed within the base, is set at a steep angle (Figs 50A,C, 51C,D), its length depending on the height of the base. At the point of reflexion the central canal is often constricted. Cultrate sclerites (Fig.53-55). Phosphatization is similar to the palmates, with generally incom plete replacement of the outer wall. In sclerites with a well developed base, the phosphatic steinkerns are often massive and may occur as isolated units. With the exception of a distinctive variant dis cussed separately (Fig. 55), cultrates are more elongate and symmetrical than palmates. The proximal end is sub-rounded to triangular, while the remainder has sub-parallel sides converging to a triangular distal termination (Figs 53A,M, 54H,1). The blade is compressed in transverse section. It is usually transversely folded with the upper surface convex, the degree of folding (Figs 53E,H, 54G) being more pronounced than in palmates. Ornamentation of the blade recalls that of the palmates, although longitudinal ribbing with tubercles on the upper surface is more prevalent. The lower surface possesses a fine transverse ribbing (Fig.53F,K), comparable to the palmates. Development of the basal region is variable. The distal area of prominent bases forms a lingu-.; late extension that overhangs the lower surface
of the blade (Figs 53B,C,J, 54E,0), while the proximal side comprises two prominent facets divided by a low median ridge (Figs 53A-C,G-J, 54A,B,I,J). The foramen lies within a rhom boidal area, the proximal edges of which are defined by low ridges (Figs 53B,C,I, 54A-D,J). The subcircular foramen may be delimited by a low circular rim that proximally abuts with the ridges bordering the surrounding rhomboidal area. Distally, however, the foramen rim may be incomplete so that the opening of the central canal is confluent with the surrounding area (Fig. 54D).. A morphological series exists from cultrates with well-developed base to those with a basal region more or less flush with the rest of the sclerite (Fig. 530-0). The lack of a simple rela tionship between sclerite size and base devel opment suggests that this is not a simple onto genetic sequence. The central canal is almost straight. The orien tation of the base results in the proximal length . being strongly recurved (Fig. 53N), and this sec tion of canal tends to be somewhat narrower and may show irregular constrictions. Within the blade the central canal tapers distally, and typi cally on its upper surface bears faint longitudinal ribs, reflecting the ornamentation of the outer wall. Lateral canals arise from the central canal, except the most proximal array attached to the basal region (Fig. 540). There is also a distinctive asymmetrical variant that does not appear to be linked to other cultrates by intermediates (Fig. 55). The base, which varies from prominent to relatively subdued, is a skewed rhomboid (Fig. 55A,E, H,L,M). In the latter, the proximal fac�ts and a rhomboidal region delimited by low ridges are still identifi able (Fig. 55L,M). The arcuate blade terminates in a recurved spine (Fig. 55A,D,E), with the central canal showing a· corresponding curva ture. Lateral canals arising from the convex side of the central canal are markedly broader than those on the opposite side ·(Fig. 55M,0), presumably to accommodate an approximately equal number of lateral canals on either side. Siculate sclerites (Figs 56-60). The outer wall is frequently phosphatized, but steinkerns of the central canal are also common. A variable num ber of lateral canals may remain attached, al-
Fig. 51� Thambetolepis delicata Jell, 1981, palmate sc1erites. Curramulka; Parara Lst., UNEL1763a (A-K),
UNEL1763b (L-O); Kulpara, Parara Lst., UNEL1860 (P) . A,B, SAMP30419. A, lower view, x50. B, inner surface of base, x165. C;F, SAMP30420. C, oblique view of base and central canal, x80. F, lower view, x40. D,E,SAMP3042L D, obliqueview, x80, E, lowerview, x55.G, SAMP30422, Idwerview, x40.H, SAMP30423, lower view, x30. I, SAMP30424, ornamentation of upper surface, x310. J, SAMP30425, basal foramen, x85. K, SAMP30426, lower view, x45. L-O, SAMP30427. L, lower view, x45. M, oblique view, x50. N, distal view, x45. 0, ornamentation of low'er surface, x215. P; SAMP30428, lower view, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
87
88
STEFAN BENGTSON et al.
Fig. 52. Thambetolepis delicata Jell, 1981, ?palmate sc\erite, SAMP30429. Horse Gully, Parara Lst., UNELI852. A, lower view, x35. B, connecting pores between central canal and lateral canal, x 180. C, detail of B, x300. D, possible tubules on sc\erite margin, x335. E, possible tubules in space formerly occupied by sc\erite wall, x380. F, detail of connecting pores, x550
though it is unusual for the entire array to be preserved. The sclerites are usually strongly recurved, asymmetric, and may show an element of torsion (Figs 56A,G,S,T, 57B,E,K,N, 58B,D-G, V). Siculates show wide morphological variation, but apart from a broader variety (Fig. 60) it is difficult to specify categories. The blade is elon gate, but its shape in cross-section varies from roughly semicircular, with the lower surface more or less flat to gently convex, to distinctly more rectangular. Ornamentation of the upper surface typically includes narrow ribs associated with a transverse sculpture of low ridges (Figs 56F,I,K, 57A,D,F, 58I,J,M,N, 59Q,R, 60P,Q); the latter are especially prominent adjacent to the base (Figs 56J,M, 57C,G, 58K). Transverse OT-
namentation of the lower surface is similar, but is more subdued (Figs 56L, 60H,I,K,L). The base is set at a steep angle to the blade, although not sharply demarcated (Figs 56S,T, 57E,58D,F,V). It is usually elongate and may taper proximally (Figs 57R,58H,59A), although a distinctive variety with truncated base occurs in some samples (Figs 57L,M, 58U-Z, 59L--O). In cross-section the base is roughly circular, but on one side a prominent flange may be present (Fig.560-S). More rarely, the opposite side of the base may bear a more subdued extension. The terminal foramen consists of a narrow opening that may be set in a wider depression (Figs 57L,58U,59F,K,L,N,O) that could be mistaken for the actual foramen. The base is usually smooth, but may bear subdued longitudinal rib bing (Fig.56D) lacking continuity with the or-
Fig. 53. Thambetolepis delicata Jell, 1981, cultrate sclerites. Curramulka, Parara Lst., UNEL1763a (A-N), (0-0). A-F, SAMP30430. A, lower view, x50. B, oblique view of base, xllO. C, oblique view of base, x 100. D, l ateral view of base, x150. E, lateral view, x40. F, ornamentation on lowersurf ace,x250. G-K, SAMP30431. G, oblique proximal view, x85. H, proximal view, x55. I, proximal view of base, x80. J, lateral view of base, x80. K, ornamentation on lower surface, x550. L, proximal view, x55. M, SAMP30432, lower view, x45. N, SAMP30433, steinkern of proximal end of central canal, x 75. 0-0, SAMP30434. 0, proximal view, x35. P, lower view, x30. 0, oblique view of base, xllO. UNEL1763b
EARLY CAMBRIAN FOSSILS, S. AUST.
89
90
STEFAN
BENGTSON et al.
namentation of the blade. The flanges typically are transversely striated (Fig. 56R). Most of the blade is occupied by the central canal, so that the lateral canals are short, espe cially distally (Figs 57J,R, 59A-D,S-W,Y). In contrast to palmates and cultrates, where the proximal central canal occupies only a small portion of the basal cavity, in siculates the cavity surrounding the central canal was either reduced or even absent. Spiniform sc1erites (Fig.61). Elongate sc1erites with modest curvature are placed in a separate category that although grading into siculates is regarded as occupying a different region of the scleritome. Preservation resembles siculates, with the outer wall often phosphatized. The blade is elongate and on its upper surface bears ornamentation of transv�rse ribs that be comes less prominent towards the distal ex tremity (Fig. 61P,R). Ornamentation of the lower surface is much more subdued, consisting of rather irregular transverse ribbing (Fig. 61 T, V). In cross-section the blade is often sub-triangular with one apex forming a fairly prominent ridge (Fig. 61 V), a1though distal1y it becomes increas ingly compressed and adopts an ovoid cross-sec tion. The base is set at a gentl.e angle to the blade and has an oval to subtriangular cross-section (Fig. 61L,U). Typically, there is a strong rota tional element (Fig. 61H,O,S) so that the major axis of the blade's transverse section lies at about
right-angles to that of the base. Ornamentation of the base is subdued and consists of longitudinal ribbing (Fig. 61M-O). The aperture is proximal, and although it appears very broad this depres sion probably surrounded the actual foramen. The central canal occupied the bulk of the blade, and although lateral canals have been identified, in some sc1erites the available space suggests that they were absent.
Taxonomy of halkieriids Questions regarding t he status of v arious halkieriid genera pale into insignificance com pared with the taxonomic confusion surrounding the numerous nominal species. An urgent· priority is to determine how the various sciotaxa (Bengtson,1985a) relate to the original scleri tome. Basic to this operation is the recognition of cultrate, palmate, siculate and/or spiniform sclerites, combined with specific data on the horizons sampled so that assemblages are reconstructed on· the basis of discrete assem blages. Cultrate and palmate sc1erites are ap parently an invariant of the halkieriid sc1eritome, and given suitable circumstances their recogni-: tion is straight forward. Despite the siculates in Thambetolepis, recognition amongst previously published material has proved difficult. They may not have been an invariable component of the scleritome, but it is also difficult to distin guish siculates from other sclerite types when the
Fig. 54. Thambetolepis delicata Jell, 1981, cultrate sclerites. Curramulka, Parara Lst., UNEL1763b. A-E, SAMP30435. A, lower view,x35. B,lower view of base, x50. C, distal view,x35. D, distal view of base,x55.
E, lateral view of base, x50. F,G, SAMP30436. F, lower view of proximal half, x45. G, oblique view, x25. H, SAMP30437,lowerview,x35. I,J,SAMP30438. I,lower view,x30. J,oblique view of proximal half,x80. K,L, SAMP30439. K, lateral view, x20. L, distal view,x25. M-Q, SAMP30440. M, proximal view of base, x65. N, lateral view, xllO. 0, proximal lateral canals and their attachment to base, x130. P, shell ultrastructure at base, x2?0. Q, shell ultrastructure,x650.
Fig. 55. Thambetolepis delicata Jell,1981,asymmetric cultrate sclerites. Curramulka, Parara Lst.,UNEL1763a
(A-C), UNEL1763b(D-G); Horse Gully, Parara Lst., UNEL1856 (H-L); Mt Scott Range, Ajax Lst., UNEL1871 (M-P), UNEL1872(Q). A-C, SAMP30441. A, lower view, x45. B, oblique view of base, xlOO. C, oblique view of base,x50. D,F, SAMP30442. D,lower view, x20. F, oblique view,x30. E,G,SAMP30443. E , lower view; x45. G, oblique view, x85. H,I,SAMP30444. H, lower view, x55. I, basal region and proximal lateral canals, xlOO. J-L,SAMP30445. J, basal region, x100. K, lateral canals,x150. L,lower view, x30. M-P, SAMP30446. M, lower view,x85. N, oblique view,x85. 0, lateral canals and marginal tubules, x345. P, detail of tubules extending from outer wal1 to lateral canal,x820. Q,SAMP30447, lower view, x20.
Fig; 56. Thambetolepis delicata Je1l, 1981, sicuJate sc1erites. Curramulka, Parara Lst., UNEL1763a. A,B,
SAMP3044K A,lateral view,x25. B, ornamentation of upper surface,x180. C-E,SAMP30449. C,lowerview, x35. D, basal region, x75. E; ornamentation in basal area, x375. F, SAMP30450, upper view, x50. G,H, SAMP30451. G, oblique view, x35. H, proximal view, x75. I-M, SAMP30452. I, upper view, x55. J, ornamentation near proximal termination of blade, x375. K, ornamentation of upper surface,x150. L, ornamen tation of lower surface, x235. M, transition from blade to base,x150. N-S, SAMP30453. N, lower view, x40. 0, base, x80. P, basal termination, x150. Q, base, x155. R, detail of -base, x295. S, proximal view, x75. T, SAMP30454, oblique view of lower side, x40. .
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 54.
91
92
STEFAN BENGTSON et al.
Fig. 55
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 56.
93
94
STEFAN BENGTSON et al.
Fig. 57.
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 58.
95
96
STEFAN BENGTSON et al.
Fig. 59.
EARL Y CAM BRIAN FOSSILS, S. AUST.
latter are viewed along either the superior or inferior edge (see Bengtson & Conway Morris, 1984, figs 3F, 5A,D,H,J for pptentially cOl!fusing examples). Many halkieri id specimens il lustrated are either incomplete or too poorly il lustrated to make any reliable suggestion as to sc1erite-type or synonymies' of many species. Inadequate stratigraphic information and insuf ficient documentation of sc1erite variability com pound the problem. Until reliable sc1eritome reconstructions become available, it is premature to discuss h alkierid evolution or detailed biostratigraphic utility.
Structure of the halkieriid scleritome . In reconstructing the scleritome of Halkieria sp. from the Tommotian of Siberia, Bengtson & Conway Morris (1984) relied on articulated ex amples of Wiwaxia corrugata. They considered the cultrates to occupy the dorsal region, and the palmates the lateral areas. They were unable to identify unequivocal siculates, but siphogo nuchitid-like elements were regarded tentatively as equivalent to the dorsolateral spines of Wiwaxia. Study of the Australian halkieriids allows fur ther comment. The earlier arrangement of pal mates and cultrates (Bengtson & Conway Morris,1984) was based on the numerical ratio of supposedly equivalent sderite types as com-
97
pared with Wiwaxia. We noted, however, that in terms of degree of symmetry and overall shape a' more convincing similarity existed between (a) the cultrate and lateral sc1erites, and (b) the pal mate and dorsal sc1erites in Halkieria sp. and Wiwaxia, respectively. In support of this revision, consider also the arrangement of the 3 articulated palmate sc1erites in Halkieria sp. (Bengtson & Missarzhevsky, 1981; Bengtson & Conway Morris, 1984). Their overlap is consis tent with the abaxial imbrication of dorsal Wiwaxia sc1erites. However, if reconstructed with adaxial imbrication, equivalent to the (lower) lateral sclerites of 'Wiwaxia, then the longitudinal axes of the sclerites must have curved outwards in a seemingly anomalous . fashion. The absence of siculate sclerites in Halkieria . sp. (Bengtson & Conway Morris, 1984) could reflect the original scleritome or less plausibly taphonomic bias, e.g., lack of diagenetic phos. phatization. Difficulties in distinguishing some spiniforms from siculates was mentioned above, but an alternative possibility arises because in this Tommotian assemblage sclerites are almost entirely represented by phosphatic steinkerns of the broad central canal. Accordingly, the ap parent absence of siculates may be an artefact, arising from a difficulty in distinguishing them from narrower cultrates. Moreover, if the cultrates were lateral, then in some earlier
Fig. 57. Thambetolepis delicata Jell, 1981, siculate sclerites. Curramulka, Parara Lst.,UNEL1763b (A-N); Mt.
Scott Ra., Ajax Lst., UNEL1871 (O-T). A- D, SAMP30455. A, upper view, x45. B, lateral view, x35. C, proximal end, x70. D, ornamentation on upper side, x150. E-I, SAMP30456. E, lateral view, x40. F, upper view, x45. G, ornamentation on proximal blade, x275. H, base, x80. I, proximal view, x80. J, SAMP30457, distal end, xl10. K-N, SAMP30458. K, oblique view, x65. L, proximal view of basal region, x120. M, basal region, x135. N, lateral view, x65. O-R, SAMP30459. 0, lower view, x40. P, proximal view, x55. Q, distal view, x50. R, lateral view, x55. S,T,'SAMP30460. S, lateral view, x95. T, lower view, x50.
Fig. 58. Thambetolepis delicata Jell, 1981, siculate sc1erites. Curramulka, Parara Lst., UNEL1848. A, SAMP30461, upper view, x50. B- D, SAMP30462. B, lower view, x40. C, proximal view, x80. D, distal view; x50. E,F, SAMP30463. E, proximal view, x80. F, oblique view, x55. G,H, SAMP30464. G, lower view of steinkern of central canal, x25. H, lateral view, x40. I-K, SAMP30465. I, oblique view of upper surface, x80. J, lateral view, x45. K, basal area, x100. L-N, SAMP30466. L, lateral view, x45. M, upper view, x45. N, oblique view, x45. O, SAMP30467, proximal view, x65. P, SAMP30468, oblique view, x55.Q-S, SAMP30469.Q, oblique view of upper surface, x80. R, lateral view, x45. S, lateral view, x45. T, SAMP30470, lateral view, x45. U-W, SAMP30471. U, proximal view of basal area, x150. V, distal view, x50. W, proximal view, x75. X-Z, SAMP30472. X, distal view, x100. Y, lower view, x50. Z, proximal view of base, x180.
Fig. 59. Thambetolepis delicata Jell, 1981, siculate sc1erites. Curramulka, Parara Lst., UNEL1846 (A-K), UNEL1848 (L-R) ,UNEL1851 (T-X); Horse Gully,Parara Lst.,UNEL1856 (S, Y). A,B,SAMP30473.A,lower view,x40. B, proximal view,x60. C,D, SAMP30474. C,lateral view, x30. D, distal view,x60. E,F,SAMP30475. E, lower view, x35. F, proximal view, x100. G,K, SAMP30476. G, distal view, x50. K, proximal view of base, x165. H, SAMP30477, oblique view, x35. 1,1, SAMP30478. I, base, xl10. J, lateral canals and central canal, x235. L-O, SAMP30479. L, lower view, x35. M, lateral view, x35. N, proximal view of basal foramen, x120. 0, oblique view of base, x150. P-R, SAMP30480. P, proximal view, x75.Q, ornamentation in distal part of upper surface, x110. R, ornamentation on upper surface, x150. S,Y, SAMP30481. S, distal view, x45. Y, lower view, x25. T, SAMP30482, lateral view, x40. U-X, SAMP30483. U, lower view, x40.V, distal view, x55. W, lower view, x30. X, lower view of centra1 canal (steinkern), x30.
98
STEFAN BENGTSON et al.
Fig. 60. Thambetolepis delicata Jell, 19 81, siculate sc\erites. Horse Gully, Parara Lst., UNEL1852 (A), UNEL1854 (B-O); Curramulka, Parara Lst., UNEL1848 (R,S). A, SAMP30484, lower view, x55. B-D, SAMP30485. B, oblique upper view, x80. C, upper view, x45. D, proximal view, x75. E-G, SAMP30486. E, lower view, x45. F, lateral view, x70. G, proximal view, x75. H,I, SAMP30487. H, lower view, x55. I, distal view, x75. J-M, SAMP30488. J, proximal view, x65. K, lower view, x40. L, distal view, x55. M, lateral view, x40. N,O, SAMP30489. N, lower view, x55. 0, base, x180. P,O, SAMP30490. P, lateral view, x40. 0, upper view, x40. R,S, SAMP30491. R, lateral view, x40. S, lower view, x30.
Fig. 61. Thambetolepisdelicata Jell, 19 81, spiniform sc\erites. Curramulka, Parara Lst., UNEL1846 (A,B,S-X), UNEL1848 (C,D), UNEL1851 (E-H), UNEL1763b (M-R); Horse Gully, Parara Lst., UNEL1854. A,B, SAMP30492, stein kern. A, x20. B, x20. C,D, SAMP30493, stein kern. C, x30. D, x40. E-H, SAMP30494, steinkern. E, x15. F, x15. G, x15. H, distal view, x30. I-L, SAMP30495. I, lower view, x15. J, distal view, x25. K, lateral view, x20. L, proximal view of base, xll0. M-R, SAMP30496. M, lateral view, x40. N, lateral view, x35. 0, upper view, x35. P, ornamentation on upper surface, x 110. 0, ornamentation on upper surf ace, x90. R, ornamentation, x220. S-X, SAMP30497. S, distal view, x25. T, lateral view, x135. U, proximal view of base, x65. V, distal view, xllO. W, lateral view, x25. X, lateral view, x15.
EARLY CAMBRIAN FOSSILS, S. AUST.
99
100
STEFAN BENGTSON et al.
halkieriids they may have been less clearly dif. ferentiated from the adjacent ventrolateral (=siculate) sclerites. Nevertheless, the pos sibility remains that in some scleritomes sicu lates may be rare or absent. Functional morphology of halkieriid sclerites Jell's (1981) arguments that the sclerites had metabolic functions; including respiration, were d iscussed by Bengtson & Conway Morris (1984), wbo regarded the sclerites as primarily protective. Documentation of the Australian halkieriids adds weight to this latter proposal. Previously unremarked is the integration of the sclerites as an interlocking shield. In pal mates this is readily apparent in articulated sets (Bengtson & Conway Morris, 1984) but may also be inferred from the configuration of the . basal region, the concavo-convex nature of which would have allowed close juxtaposition of adjacent sclerites. Articulation of neighbouring palmates would have been promoted also by the inferior and s uperior facets of the blade (Bengtson & Conway Morris,1984). An absence of articulated cultrates makes their original configuration more speculative. It seems likely that the proximal facets of the base inter locked with the distal extremities of the sclerites located immediately to the anterior, so that transverse rows of cultrates alternating in posi tion along the length of the animal. The shape of siculates suggests that they may have formed a nested file, directly comparable to the single row of ventrolateral sclerites on either side of Wiwaxia (Conway Morris, 1985). Thus the scleritome formed a closely integrated armour, consistent with a protective function. This defence was probably supplemented by the spiniform elements projecting as an array from either side of the body (Bengt_ Morris,1984). The .calcareous sclerites pre sumably helped in protection, but their inter locking. nature may have provided a major impediment to gas exchange between the under lying cuticle and sea-water. One possibility is that halkieriids were equipped with gills, unless serial elevation of the sclerites and pumping of sea-water over the cuticular su rfaces met respiratory demands.
Evidence for moulting in Wiwaxia and the halkieriids is reviewed elsewhere (Bengtson & Conway Morris, 1984; Conway Morris, 1985). Questions remain with respect to the steps in the s e c r e t i o n of a s c l e r i t e a n d the possi ble withdrawal of soft-tissue during ecdysis, a prob lem especially acute in Thambetolepis, because of its complex array of internal canals and basal cavity. Initial secretion must have been a complex process, whereas any withdrawal of soft-tissue from the sclerite via the foramen during the ec dysal cycle may have been confined to the central canal, unles$ narrow connecting pores allowed retraction of material from lateral canals. Hypotheses of halkieriid functional mor phology should also explain differences from Wiwaxia. The most striking contrasts are (a) lack of sclerite mineralization, (b) c;l transition from a tightly integrated scleritome to a more loosely structured assemblage that still covered the body and (c) inferred absence of a complex system of internal canals. One possibility is that a less integrated scleritome may have allowed greater flexibility in locomotion and changes in shape. Evidence is sligpt, but the possibly simpler struc ture of the sclerites may have facilitated moult ing. If Wiwaxia was a neotenous descendant of the Lower Cambrian halkieriids (Bengtson & Conway Morris, 1984), this could have arisen by hormonal alteration, especially as the periodic moulting of the scleritome may have been under endocrinal control. Phylogeny of coeloscleritophorans [SCM, SB] At present, the coeloscleritophorans comprise 1, Chancelloriidae (Lower-Upper Cambrian), with sclerites in rosettes that either coated or were embedded in the wall of vase-shaped organisms, 2, Halkieriidae (Lower Cambrian), with four sclerite types, 3, closely related Wiwaxiidae (Middle Cambrian), with similar scleritome, al beit unmineralized and less integrated, 4, Sachitidae (Lower Cambrian), with elongate sclerites with circular to oval cross-sections and minute foramen that appear 'to have been em bedded individually in the body wall, and 5, Siphogonuchitidae (Lower Cambrian), with elongate sc1erites in bundles, triangular to quad rangular cross-section, and a larger foramen.
Fig. 62. Thambetolepis delicata JeJl, 1981. Curramulka, Parara Lst., UNEL1763a (A-D), UNEL1763b (E-N). A,B, SAMP30498. A, lateral canals showing pinching out of canal, x175. B, proximal ends of lateral canals showing openings to connecting pores, x90. C,D, SAMP30499. C, lower view, x20. D, lateral canals, x65. E-G, SAMP30500. E, central canal and Lateral canals, x50. F, central canal showing possible shel1 ultrastructure, x120. G, lateral canal showing possible shell ultrastructure, x] 50. H, SAMP30501, lateral canal showing possible she]] ultrastructure, x470. T, SAMP30502, lateral canals, x120. J, SAMP30435, lateral canals, x135. K,L, SAMP30503. K, lateral canals, x100. L, proximal ends of lateral canals showing connecting pores, x120. M,N, SAMP30504. M, x40. N,.Iateral
EARLY CAMBRIAN FOSSILS, S. AUST.
101
102
SACH
STEFAN BENGTSON et al.
HALK
WIWA
SIPH
CHAN
A hollow calcareous sclerites with scaly surface and restricted aperture
SAC:H
SIPH
WIWA
HALK
CHAN
B hollow calcareous sclerltes with scaly surface and restricted aperture
SACH
WIWA
HA L K
CHAN
SIPH widened aperture imbrication differentiation
c
hollow calcareous sclerites with scaly surface and restrlcted aperture
63. Candidate c1adograms for interrelationships of coeloscleritophoran taxa (Chan, chancelloriids; Halk, halkieriids; Sach, sachitids; Siph, sipho gonuchitids; Wiwa, wiwaxiids; PCSS, palmate cultrate-siculate-spiniform). Derived characters marked by spherules; bpldface indicates convergent characters. Fig.
If the validity of these five families is accepted, then there are a number of possible inter-relation ships, of which a few are represented in the cladograms of Fig. 63. Unquestionable pksio morphies in the sclerites appear to be (a) cal careous composition, (b) hollow interior, and (c) surface sculpture of imbricating scales or tubercles, these being found in all groups, except for the secondarily non-mineralized Wiwax-
iidae. The similar scleritome composition of halkieriids and wiwaxiids suggests that they are sister groups. Thereafter, decisions must depend up on more uncertain assessm ents of the homologies of (a) the rosette-like arrangement of most chancelloriid sclerites and the bundling of siphogonuchitid sclerites (Chen, 1979a; Voronin et al., 1982; Yang et al., 1983), (b) the differen tiation· of broad versus narrow sc1erites in sachitids, siphogonuchitids, and wiwaxiids halkieriids, respectively, and (c) the scale-like imbrication of sclerites in siphogonuchitids and wiwaxiids-halkieriids, respectively. Stratigraphic appearance in no case seems to indicate partiGular ancestor--descendant rela tionships, although this statement must be set in the context of continuing uncertainty regarding st ratigraphic correlations. The m ost p arsi monious cladogram (Fig. 63A) does not contain any convergence but assumes no relationship between chancelloriid rosettes and sipho gonuchitid bundles. The other two cladograms suggest that the former evolved from the latter but involve convergences in sclerite differentia tion (Fig. 63B,C; note that this could also be brought about by one incidence of differentiation and subsequent loss of this character in chancel loriids) and in the development of a tightly im bricating scleritome (Fig. 63C). Both these characters, however, are simple and may easily have arisen convergently. Cladogram A is never theless the favoured interpretation, and it iden tifies as sister groups the two main divisions of the Coeloscleritophora recognized by Bengtson & Conway Morris (1984) as the Orders Sachitida and Chancelloriida. It should be stressed that there is no firm evidence that this is the fun damental division of the group. In cladograms A and C the Sachitidae do not have any autapomorphies, suggesting that they may be regarded as the stem group of the Sachitida (Fig; 63A) or of the taxon containing the Sachitidae, Wiwaxiidae, and Halkieriidae (Fig. 63C). , In the absence of additional evidence, an ex tensive discussion of the merits of alternative cladograms seems unwarranted, and these are depicted here in the hope of provoking further discussion. Further advances may be dependent on an understanding of the palaeoecology of each group. Thus, descriptions of articulated wiwaxiids (and halkieriids) and chancelloriids suggest that the former were members of the vagrant benthos (Conw.a y Mo rris, 1985), whereas the latter were part of the sedentary epifauna (Bengtson & Conway Morris, 1984; Conway Morris, 1985). Unfortunately, in neither siphogonuchitids nor sachitids is a mode of life clearly established, and so the possibility of
EARLY CAMBRIAN FOSSILS, S. AUST.
recurrent shifts in mode of life during phylogeny is not easy to establish.
CAMBROCLAYES [SCM] Cambroc1aves are distinctive sclerites of the middle to upper Atdabanian of China, Australia and Kazakhstan, and range into the upper Lower Cambrian of China. Sclerites consist of either a more or less circular boss (zhijinitid morph) or a more elongate shield (cambroclavid morph), both bearing an elongate spine (but see Conway Morris & Chen, in press). Scleritomes solely of zhijinitid morphs (Zhijinites Q i a n , 1 9 7 8 a ) probably preceded ones where cambroclave morphs predominated, with zhijinitid morphs a minor constituent. Zhijinites is maintained for scleritomes of zhijinitid morphs, with Paraz hijinites (P. guizhouensis Qian & Yin in Xing et al., 1984b, p.177, p1.22, figs 5-8; speCific name consistently misspelt quizhouensis in Qian & Yin, 1984b) probably a junior synonym. Kaiyan gites novilis (Qian & Yin, 1984a; nomen nudum in Yin et aI., 1982) was regarded by Qian & Yin (1984a) as incertae sedis, but Xing et aL (1984b; specific name misspelt novilisa on p. 248; see also Wang et a/., 1984b) included it within the zhijinitids. This placement is doubtful. The scleritome of Cambroclavus Mambetov in Mambetov & Repina, 1979, is dominated by ,cambroc1ave morphs. Proposed junior synonyms of this genus are provided be]ow. Pseudoclavus Mambetov in Mambetov & Repina, 1979, may be distinct and restricted to the Atdabanian of Kazakhstan. Qian & Yin's (1984b, p.218) sug gestion that it is a junior synonym of Zhijinites is not accepted. A Tommotian specimen from the Tuora-Sis Ridge (Siberian Platform) described by Mesh kova (in Repina et al., 1974, pl.19, fig.11) as Hyolithellus vladimirovae, has been referred to Zhijinites (Chen, 1979b; Qian & Yin, 1984b). Inclusion in H. vladimirovae is evidently er roneous (Rozanov & Missarzhevsky, 1966, pl.12, fig.6; Meshkova, 1969, p1.51, fig.5), but it may be more comparable toArchaeopetasus gen. nov. A specimen referred to Sachites hastatus by He (in Yin et al., 1980, pl.18, fig.9) may be a Zhijinites. Phylum, Class, Order uncertain Family ZHIJINITIDAE Qian, 1978a Diagnosis. Elongate (cambroclavid morph) to Circular (zhijinitid morph) sclerites, bearing elongate spine on upper surface. Spine smooth or transversely corrugated, upper surface of sclerite ornamented with radiating striations, typically
103
rather weak. Lower surface typically smooth. Interior hollow, original composition of wall probably calcareous. Following Qian & Zhang (1983) and Qian & Yin (1984b) the Zhijinitidae and Cambro clavidae Mambetov in Mambetov & Repina, 1979 are synonymized because of close agree ment in most characters (but cf. Duan,1984). Cambroclavus Mambetov in Mambetov & Repina, 1979 Cambroclavus Mambetov in Mambetov & Repina, p.122. ?1982 Sugaites Qian in Gao et al., p.525. [nomen nudum] ?*1983Isoclavus Qian & Zhang, p.91. *1984 Phyllochiton Duan, p.174. *1984 Sinoclavus Duan, p.172. ?*1984 Tanbaoites Duan, p 173. *1984 Sugaites Qian & Xiao, p.79. ?*1984 Wushichites Qian & Xhio, p.76. ?1984 Zhijinites Qian & Xiao,p.81. [partim Z. inter medius and possibly Z. clavi/ormis] 71986 Zhijinites Jiang & Huang. [partim Z. cardi/or mis [sic], Qian & Yin, p1.2, fig 8, and possib ly Z. clavi/armis, Qian & Xiao, p1.2, fig.3]. 1979
.
.
Type species. C. antis Mambetov in Mambetov & Repina, 1979. Other nominal species. C. clypeatus Duan, 1984; C. olecranus Duan, 1984; C. hubeiensis Duan, 1984; C. dolicanthus Duan, 1984; C. fangxianen sis Qian & Zhang, 1983; C. paradoxus Qian & Yin, 1984b (but C. undulatus Mambetov in Mambetov & Repina, 1979 (in part), may be referred to Zhijinites (see below; see also Jiang in Luo et a/., 1982, p.182) and C. clavus Mam betov in Mambetov & Repina, 1979 may be unrelated to the cambroc1avids); Phyllochiton shawanensis Duan, 1984; Sinoclavus clavatus D u a n , 1 9 8 4 ); Sugaites bicornis Q i a n & Xiao,1984 (nomen nudum in Gao et al., 1982, p.525); S. solei/ormis Qian & Xiao, 1984; S. sicyojdeus Qian & Xiao, 1984; S. hastatus Qian & Xiao, 1984; and S. saccatus Qian & . Xiao, 1984. Other doubtful species. lsoclavus bilobus Qian & Zhang, 1983; Tanbaoites p6rosus Duan, 1984; T. spiculosus Duan, 1984; Wushichites minutus Qian & Xiao, 1984; W. polyedrus Qian & Xiao,1984; Zhijinites clavi/ormis; Z. intermedius Qian & Xiao, 1984. Distribution. Lower Cambrian (Atdabanian) of Kazakhstan (Maly Karatau, Talassky Alatau), South and central Australia, China (Hubei and
104
STEFAN BENGTSON et al.
Xinjiang); upper Lower Cambrian of China (Hainan Island).
Diagnoiis. Sc1erites with more or less elongate shield, typically divided into subcircular anterior region and more elongate posterior, separated by variable lateral constriction, giving sc1erite dumb-bell appearance. Sclerites bilaterally sym metrical to strongly asymmetrical. Anterior region bears prominent dorsal spine, lower sur face with articulating facet or radiating ridges. Posterior region usually expanded transversely, occasionally with short extensions. Facet on upper surface articulates with anterior lower sur face of adjacent sclerite; and adjacent sclerite files interlock between expanded anterior regions and corresponding lateral indentations. Occasional sclerites reduced to anterior region, as zhijinitid morphs. Cambroclavus absonus Conway Morris, sp. novo (Figs 64-70) Etymology. Latin absonus, different; refers to its variability. . Material. Holotype SAMP30531 (Fig. 65J) from the Ajax Lst. at UNEL1874 in the Mt. Scott Ra.; paratypes SAMP30525-30530, 30532-30573 and c. 300 other specimens. Distributlon: Hor s e G u l l y , P a r a r a L s t . (UNEL1852-1854,1762); Mt. Scott Ra., Ajax Lst.(UNEL1872-1874,1876,1877).
Diagnosis. Elongate shield, dumb-bell shaped, but constriction absent to strongly developed, bilateral to strongly asymmetrical. Anterior sub circular, upper spine sometimes surrounded by weak trough. Upper surface may be radially or namenta t ed, lower surface a broad facet. Posterior expanded, sometimes markedly so or projecting laterally as pair of short stub-like ex tensions, surface may bear subdued ridges aris ing from median zone. Broad posterior facet on upper surface. Rarely reduced to zhijinitid morph by reduction to anterior region. Preservation. The phosphatized sc1erites are diagenetic replacements of an originally calcar eous skeleton (cf. Rozanov, 1986). Smooth phos phatic coat may represent an epitaxial coating, but preservation of surface structures indicates replacement of the wall. Although generally the central cavity is defined by a single wall, some sc1erites, especially in the anterior, are two layered with the intervening space (Figs 64R, 66D, 69K) defining the thickness of the original wall. This space may be filled with an irregular meshwork, with tubules (Fig. 67G-I,T) that may represent endolithic algae (cf. Runnegar,1985a; Conway Morris & Chen, 1989). Description. Most sc1erites approach bilateral symmetry; but a few (Figs 64T, 67K,L,Q) are markedly asymmetrical. Anterior and posterior regions (Fig. 64A,C,K,O-T,X,Y) are separated by a constriction that is usually moderately pronounced, giving the sclerite a dumb-bell
Fig. 64. Cambroclavus absonus Conway Morris, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1872 (A-J),
UNEL1873 (K-W), UNEL1874 (X,Y). A, SAMP30505, x60. B,C, SAMP30506, x60. D, SAMP30507, lower view, x60. E, SAMP30508, x120. F, SAMP30509, x60. G-I, SAMP30510. G, oblique antero-Iower view, x60. H, lower view, x60. I, lower anterior view, x120. J, SAMP30511, lower posterior view, x60. K, SAMP30512, x60. L, SAMP30513, x90. M, SAMP30514, x90. N, SAMP30515, x60. 0, SAMP30516, x60. P, SAMP30517, x60. Q, SAMP30518, x60. R,S, SAMP30519.R, x60. S, x200. T, SAMP30520, x60. U, SAMP30521, x60. V, SAMP30522, x60. W, SAMP30523, reduced posterior resulting in approach to zhijinitid-like morph, x90. X,Y, SAMP30524. X, lower posterior view, x60. Y, lower view, x60.
Fig. 65. Cambroclavus absonus Conway Morris, sp. novo Mt. Scott. Ra., Ajax Lst., UNEL1874. A,B,
SAMP30525. A, x60. B, x90. C, SAMP30526, x60. D,E, SAMP30527. D, x90. E, x90. F, SAMP30528, x90. G, SAMP30529, x60. H,I, SAMP30530, x60. J, holotype, SAMP30531, x90. K, SAMP30532, x90. L,U, SAMP30533, x90. M, SAMP30534, upper- anterior view, x90. N, SAMP30535, x60. O,P, SAMP30536. 0, upper view, x60. P, detail of wall ultrastruCture, x600. Q-S, SAMP30537. Q, x90.R, x90. S, detail of anterior, x400. T, SAMP30538, x60. V,W, SAMP30539. V, x60. W, detail of wall ultrastructure on spine, x1200.
. Fig. 66. Cambroclavus absonus Conway Morris, sp. nov. Mt. Scott Ra., Ajax Lst., UNEL1874. A, SAMP30540,
x60. B, SAMP30541, x60. C,D, SAMP30542. C, x60. D, detail of spine, x200. E, SAMP30543, x60. F, SAMP30544, x60. G, SAMP30545, x90. H, SAMP30546, x60. I-K, SAMP30547. I, x90. J, x90. K, detail of spine base, showing possible repair features, x400.L, SAMP30548, x60. M,N, SAMP30549. M, x60. N, detail of spine base, x600. 0, SAMP30550, ventrolateral view, x60. P, SAMP30551, ventrolateral view, x60. Q, SAMP30552, oblique view'.of lower side, x60.R,·SAMP30553, lower side, x60. S, SAMP30554, lower view, x60. T, SAMP30555, lower-lateral view, x60. U, SAMP30556, lower view. showing interior, x60. V, SAMP30557, lower view, x60. W, SAMP30558, lower view, x69. X, SAMP30559,. oblique lower view, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
105
106
STEFAN BENGTSON et al.
Fig. 65.
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 66.
107
108
STEFAN BENGTSON et al.
Fig. 67.
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 68.
109
110
STEFAN BENGTSON et al.
Fig. 69.
EARLY CAMBRIAN FOSSILS, S. AUST.
shape, but it may be very pronounced (Fig 640,R,X,Y, 65A,U, 67F), so that the anterior region forms a well defined circular unit. In a few sc1erites the constriction is almost absent (Fig. 66A,B). The upper surface bears an elongate spine, recurved posteriorly (Figs 64L,M, 67C). Seldom preserved complete, in suitable specimens it ap proaches the length of the entire shield. The spine cross-section is more or less circular. In sc1erites where the ratio of spine base to total anterior area is small, the base may be delimited by a shallow annular furrow (Fig. 650-S). Incompleteness of spines is normally preservational, but sometimes a basal spine stump (Fig. 66J,K) conceivably reflects conditions during life. Numerous pus tulose projections (Figs 67R,S, 68F,G) on some basal stumps may be a product of postmoitem phosphatization, but in others each pustule has a bas e bearing a short conical spine (Fig. 68H). Such structures may represent repair following the loss of the main spine. The upper surface may bear furrows and ridges radiating from the spine base (Fig. 65S). The lower region usually is occupied by a broad facet, more or less open anteriorly, but delimited on its lateral and posterior edges (Figs 64G J,X,Y, 66X). The posterior region generally is more elon gate. Lateral margins may be subparallel, but usually the terminal area is laterally expanded and may take the form of discrete stubby projec. tions (Figs 64A,C,D,R, 65D) or wing-like exten sions that point posteriorly (Figs 640,X,Y, 65T, 66W,X, 67F). The posterior margin is entire, unless a slight notch or groove (Fig.64V) is present. The upper surface is rounded, except in sc1erites where a broad median ridge is flanked by arcuate depressions (Figs 640,U, 65H,J).
111
Posteriorly, however, there is a broad facet (Figs 64B,C,P,R, 65E,G, 67G). The upper surface may be smooth or bear low ridges that diverge from the median area (Figs 64R,S, 65D,K,L,U). Specimens with an abbreviated posterior section (Figs 64W, 69A, G,I) can be traced to those with a circular boss bearing a prominent spine (Fig. 69B,C,E,F,K,L, O,P), and ultimately sc1erites with part of the basal area missing so that the anterior margin is defined by the spine base (Fig. 69H, M,N).. Articulated specimens. Mambetov (in Mambe tov & Repina,1979, p1.14, figs 6,8,9) illustrated articulated sc1erites of C. antis from Kazakhstan. Preservation has not favoured- such fragments in Australian material, but occasionally two fused sc1erites of an antero-posterior file are found (Fig. 68A-E). Such imbricated associations con firm the function of the anterior (lower) and posterior (upper) facets. The shape of individual elements and the arrangement of the Kazakhstan sc1eritomes suggest lateral rows interlocked by the rounded region of one sc1erite matching the concave embayment (constriction) of its imme;.. diate neighbour (Fig. 70). Such an array in an ideal case would lead to· each antero-posterior file being displaced by a half-unit length from the adjacent files, so that spine disposition defines a quincuncial pattern. Despite considerable morphological variation, most sclerites appear to have had the ability to interl ock. This implies that neighbouring sclerites had similar shapes (see also Mambetov & ·Repina, 1979, pl.14, figs 8,9), but the slight asymmetry of most sclerites would have per mitted transitions to other morphs quite rapidly. Zhijinitid morphs may have acted as 'hole fillers' in the scleritome, especially in areas of
Fig. 67. Cambroclavus absonus Conway Morris, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1874. A, SAMP30560,
oblique lateral view, x60. B, SAMP30561, x60. C, SAMP30562, x60. D,N,O, SAMP30563. D, x60. N, x60. 0, detail of upper anterior surface, x600. E, SAMP30564, x60. F, SAMP30565, x60. G-I, SAMP30566. G, x60. H, section across spine, x400. I, detail of spine wall, x450. J, SAMP30567, x60. K, SAMP30568, x60. L,M, SAMP30569. L, x90. M, oblique view, x90. P, SAMP30570, x90. Q, SAMP30571, x60. R,S, SAMP30572. R, x90. S, anterior region in oblique view, x300. T, SAMP30573, detail of spine wall, x900.
Fig. 68. Cambroclavus absonus Conway Morris, sp. novo Ross River, Todd River Dolomite, UNEL1862 (A,B);
Mt. Scott Ra., Ajax Lst., UNEL1874 (C, F-H), UNEL1877 (D,E). A,B, SAMP30574, two articulated sc1erites;
A, upper view, x135; B, lateral view, x135. C, SAMP30575, two articulated sc1erites, lateral view, x90. D,E,
SAMP30576. D, lateral view, x135. E, upper view, x135. F-H, SAMP30577. F, x135. G, detail of anterior showing spine base and possible repair features, x400. H, detail of possible repair features, x2000.
Fig. 69. Cambroclavus absonus Conway Morris, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1874 (A-G, I-P);
Horse Gully, Parara Lst., UNEL1853 (H). A, SAMP30578, dorsolateral view, x90. B,C, SAMP30579, zhijinitid morph. B, lower view, x60. C, lateral view, x60. D, SAMP30580, upper view, x60. E, SAMP30581, zhijinitid morph, x90. F, SAMP30582, zhijinitid morph, x135. G, SAMP30583, x60. H, SAMP30584, zhijinitid morph, x40. I,J, SAMP30585, zhijinitid morph. I, x60. J, detai1 of spine wall, x400. K, SAMP30586, zhijinitid morph, x135. L, SAMP30587, zhijinitid morph, x135. M,N, SAMP30588. M, anterior view, x135. N, lateral view, x135. O,P, SAMP30589. 0, x135. P, base, x200. .
112
STEFAN BENGTSON
et
al.
dislocation between sclerites of markedly differ ing shape. Composition and mode a/secretion. A promi nent fibrous arrangement in the spines and upper region (Figs 64L, 65P,W, 670, 691) is indicative of diagenetic phosphatization of an originally calcareous wall, but usually no shell structure is preserved. Sclerite shape, absence of concentri cally arranged growth increments, and enclosure of a central cavity (Fig. 66U) all suggest that size increase could have been achieved only by resorption of the wall. The interlocking scleri tome means that such modification would re quire co-ordination in adjacent files. An al ternative and preferred hypothesis is that each sclerite was secreted by central cavity tissue and did not change in size after its formation. Secre tion of calcium carbonate was probably under genetic control, but sclerite shape is more likely to have heen determined by position relative to its neighbours (cf. Reif, 1974). Reif's (1974) discussion of morphogenesis of shark skin denticles may also be relevant as a growth analogy to cambroclave scleritomes. If individual sclerites had no growth potential, then newly secreted sclerites must have been interpo lated as the animal increased in size, to avoid jeopardizing the function of the scleritome as an interlocked array. Inferred close articulation be tween existing sclerites suggests that direct inter polation would have been difficult, but formation of distinct files would have avoided disruption. In such a case, earlier formed sclerites may have shifted to marginal zones, and possibly ultimate ly discarded. If the cambroclave animal was an active bilaterally symmetrical creature, with a high length to breadth ratio, i.e. some sort of worm, then the ,generative zone may have been posterior, with successive interpolation of antero-posterior files as growth proceeded. Even if size increase was not matched by direct inter polation, the tissue beneath the scleritome may have retained a secretory ability, and in the event of damage or loss new sc1erites, perhaps more
irregular in shape, could be incorporated. Functional morphology. The proportion of original scleritome represented by the arrays of articulated files (Mambetov& Repina, 1979) is not known. In these fragments, the morpholog ical variation of the sclerites appears limited. Deciding whether the degree of morphological variation documented herein is because different shaped sderites·· occurred on an individual, as a g a i nst each i ndividual showing limited variability but differing from other members of the popUlation, cannot be decided on present evidence.
Sclerites were probably mantled by thin epidermis and occupied a peripheral position, thus forming an exoskeleton analogous to that of echinoderms. The imbricated and interlocking nature of the scleritome suggests that it conferred a protective function against predators and/or abrasion. Moreover, although the spines could have contributed to defence, their consistently recurved attitude indicates that their function may have been also to grasp a substrate. Chinese workers (Qian & Xiao, 1984; Qian & Yin, 1984b) have compared them with grasping hooks, including those of parasitic acan thocephalans. While this phyletic assignment receives no support here (see also Conway Mor ris& Chen, in press), infaunal cambroclaves may have used the spines as anchors during burrow ing. If the spines were adapted to grip sediment grains, and it is assumed that juveniles and adults occupied the same sediment, then size could have shown an allometric change designed to compensate for growth in animals that occupied a substrate with invariant particle dimensions. The surface spikes of infaunal bi"alves show such a relationship (Aller, 1974). Preliminary analysis of spine size (measured as basal diameter because spines are incompletely preserved) versus sclerite length (assumed proportional to body size) i.!1dicates positive al lometry, i.e. spine size disproportionally greater in larger sclerites. Spine separation between ad jacent sclerites increased with sc1erite size, so this allometry would increase the relative spac . ing at a slower rate than if growth was linear. Relationships. Within the cambroclaves extent of variation is seldom available, but it is likely that mUltiple specific names applied to as semblages from a single horizon represent single scleritomes. Cambroclaves were fi rst described from Talassky Alatau and Maly Kanitau, Kazakhstan, in the Atdabanian Rhombocorniculum cancel lalum to Microcornus parvulus Zones (Mam b e t o v in M a m b e t o v & R e p i n a , 1 9 79; Missarzhevsky& Mambetov, 1981). The status of C. clavus (Mambetov& Repina, 1979, pI. 13, figs 3,5,7-9) is uncertain, and similarities with Spicule Type A suggest that re-assignment may be necessary (cf. Conway Morris & Chen, in press). C. antis resembles C. absonus, but differs in some sc1erites having a zone of articulation between sc1erites in an antero-posterior file con sisting of an upper median fold on the posterior area linked to a corresponding lower median ridge on the anterior area of next element. This latter ridge is flanked by radiating furrows and folds, whereas in C. absonus this area is smooth. Zhijinitid morphs, which Mambetov& Repina
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 70. Reconstruction of articulated sclerites of Cambroclavus absonus. Note that over wider areas of the scleritome changes in sclerite shape probably oc curred, although the integrity of the scleritome would have been maintained by mutual accommodation
(1979) referred to as C. undulatus, were reas signed to Zhijinites by Jiang (in Luo et al., 1982) and Duan (1984). Jiang (in Luo et al., 1982) also reassigned other Kazakhstan sclerites to Z. lon gistriatus Qian, 1978a (Mambetov & Repina, 1979, pl.13, figs 11,12) and Z. lubricus Qian et al., 1979 (Mambetov& Repina, 1979, pl.13, figs 2,10,13), even though sclerites of the former
113
species are indistinguishable from those retained by Jiang in C. undulatus. These proposals, there fore, are not accepted. Duan (1984, p.170) made the more salient suggestion that the specimens illustrated by Mambetov& Repina (1979, pl.13, figs 2, 10,13) should be placed in separate species, but as they appear to co-occur with C. antis (Mambetov & Repina, 1979, p.109, fig.S) they may represent zhijinitid morphs in this cambroclavid scleritome. However, whether the remaining sclerites of Z. undulatus (Mambetov & Repina, 1979, pl.13, figs 1,4,6,11,12) belonged to the same scleritome as C. antis seems questionable. C. antis has a consistently longer stratigraphic range in some sections (Mambetov & Repina, 1979, figs 2,3) than Z. undulatus. The latter species is confined to the lower half of the R. cancellatum Zone, whereas C. antis extends into the lower part of the over lying M. parvulus Zone. Cambroclaves from the Yurtus Formation of Aksu-Wushi, Xinjiang Province, China were placed in five species of Sugaites (Qian & Xiao, 1984). Indistinct outlines appear to be a result of heavy coats of phosphate, but strong similarity t o Cambroclavus (especially C. antis from Kazakhstan), suggests that Sugaites is a junior synonym. The five nominal species are-probably synonymous, so the scleritome may be referred t o a s C. bicornis. Co-occurring sclerites of Wushichites (W. minutus, W. polyedrus) were regarded by Qian &- Xiao (1984, pI.1, fig.7; pt 3, figs 11-13) as of uncertain systematic position. T h e y a r e p o s s i b l y f r om t h e C. bicornis scleritome, because a numl?er of specimens pos sess a posterior notch (Qian & Xiao, 1984, pI.1, figs 9,13; pl.3, figs 18,19) which, if accentuated and combined with overall shortening of the sclerite, would lead to a form similar to W. minutus. Zhijinitid morphs (Z. clavi/ormis, Z. intermedius) also occur in this unit. Z. inter medius (Qian&Xiao, 1984, p1.3, figs 28,29) may be shortened cambroclave sclerites, although whether Z. clavi/ormis (Qian& Xiao, 1984, p1.2, fig.13; p1.3, fig.27) can also be accommodated in the scleritome of C. - bicornis is uncertain. Qian & Yin (1984b) described cambroclaves from the nearby Upper Phosphorite of the Xiaoerbulak Formation as C. paradoxus. Qian& Xiao (1984, fig.2) depict theXiaoerbulak Formation as over lying the Yurtus Formation, but the horizon sampled by Q i a n & Yin (1984) m a y be equivalent. C. paradoxus and C. bicornis are probably synonymous.. Priority is given to C. bicornis (date of publication: January, 1984, as against March, 1984, for C. paradoxus). Using the- highly variable C. absonus as a standard of comparison, then four species at tributed to Cambroclavus (C. clypeatus, C.
114
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSS ILS, S. AUST.
115
dolicanthus, C. hubeiensis, C. decranus), three Sinoclavus (S. clavatus, S. jlabeUi [ormis, S. humilis), and PhyUochiton shawa nensis from the X i h aoping For mation of species of
Shennongjia district, Hubei Province (Duan, 1984), all could be referred to a single species of Cambroclavus. Their co- occurrence in Bed 13 of the Sha-tan section ,(Duan, 1984, table 1) supports this synonymy, while more scattered occurrences in adjacent sections suggest exces sive reliance on form taxa. From the same beds Qian & Zhang (1983, p1.3, figs 1-8; pl.4, figs 1-5; t e x t-fi g . 3 ) d e s c ri b e d s yn o n y m o u s cambroclaves a s C. fangxianensis, the correct name by priority. Sclerites, supposedly belonging to the Zhi jinitidae, were placed by Duan (1984) in Tan baoites porosus and T. spiculosus). Apparently identical sclerites were described as Isoclavus bilobus (Qian & Zhang, 1983, p1.3, figs 9-16; text-fig.4). These sclerites also appear to be cambroclavid morphs, and they approach in shape Wushichites (Qian & Xiao, 1984). Al though Duan (1984) indicated his material to be restricted to one horizon (Bed 8 of the Tan-Gao section), it co-occurs with C. fangxianensis and may be derived from the same scleritome. C.fangxianensis has been described also from the Damao Group (Damaodong section) in Yaxian County, Hainan Island (Jiang & Huang, 1986). Co-occurring sclerites, referred to Zhijinites cordiformis (misspelt cardiformis in Jiang & Huang, 1986) and Z. claviformis, may be derived from the same scleritome. C. absonus has striking similarities to C. [angxianensis (and its proposed synonyms), and in isolation many sclerites from Australia and China would be indistinguishable. Although these species may be synonymous, a distinction is maintained because equivalents to the zhijinitid morphs referred to Isoclavus (its junior synonym Tanbaoites and perhaps Wushichites) have not been recognized in Australian as semblages. Inclusion by Mambetov & Repina (1979) of Pseudoclavus singularis in the cambroclaves seems reasonable, but its proposed synonymy with Zhijinites (Qian & Yin, 1984b) is not ac cepted. The broad facet on the upper surface probably articulated with a corresponding depression on the lower side of the next sclerite, suggesting that like Cambroclavus they were arranged in antero-posterior files. The stratigr-
Fig. 72. Eccentrotheca guano Bengtson, sp. novo Horse Gully, KuiparaLst., 6429RS103. SAMP30611. A, x75. B, detail 0 fA, x300.
aphic range of P. singularis makes inclusion in the scleritome C. antis or C. undulatus unlikely.
WithZhijinites.Associations from Australia, ap parently China, and possibly Kazakhstan, sug gest that the cambroclave scleritome bore a few zhijinitid morphs, similar to sclerites referred to Zhijinites. In many Chinese samples, however, assemblages are composed exclusively of zhijinitid morphs. Such occurrences are from stratigraphically older beds and suggest that this scleritome was ancestral to the cambroclavid condition. Distinction between Zhijinites and
Fig. 71. Eccentrotheca guano Bengtson, sp. novo Horse Gully, Kuipara Lst., 6429RS103. All x50. F-J stereopairs. A,B, SAMP30590. C, SAMP30591. D, SAMP30592. E, SAMP30593. F, SAMP30594. G, SAMP30595. H, hoiotype, SAMP30596. I, SAMP30597. J, SAMP30598. K, SAMP30599. L, SAMP30600. M, SAMP30601. N, SAMP30602. 0, SAMP30603. P, SAMP30604. Q,R, SAMP30605. S, SAMP30606. T, SAMP30607. U, SAMP30608. V, SAMP30609. W, SAMP3061O.
116
S TEFAN BENGTSON
et al.
other parts of China, including Sichuan (Yin et al., 1980), Hubei (Qian et al., 1979), and Yunnan (Jiang in Luo et aI., 1982, 1984) may also be synonymous. Note thatZ. annae, Z. costatus and Z. d ictyoformis (Chen, 1979b) are nomina nuda and see Qian & Yin (1984b) for proposed synonymies. Lack of articulating facets in Zhijinites sug gests that the sclerites studded the surface of the animal, possibly separated by unarmed tissue. In contrast, descendant cambroclaves have a more complex scleritome with well defined articula tion surfaces and presumably a more ordered arrangement of sclerites, with zhij initid morphs either occupying discrete zones or employed to fill occasional gaps in the scleritome. Like cambroclaves, zhij initids may have been infaunal. Alternatively, if the latter group was infaunal, a transition to an articulated scleritome may have reflected a shift to the epifauna so that the spines, formerly used for gripping sediment, were pre- adapted for defense.
Fig. 73. Eccentrotheca guano? Bengtson, sp. novo Horse Gully, KulparaLst., 6429RSI03. SAMP30612, x50.
Cambroclavus, therefore, is maintained (cf. Rozanov, 1986), but assignment to either genus is dependent on accurate scleritome reconstructions and cannot rely on description of isolated form taxa, especially given the persistence of the zhijinitid elements in the cambroclave scleritome. Zhijinites has not been recognized in Australia, but the customary plethora of species evident in the literature may be reduced, because many of the ostensibly distinct forms may have derived from a shared scleritome. For example, the plexus of species from Guizhou that includes Z. longistriatus, Z. minutus, Z. pand uriformis, Z. cordiformis, Z. triangularis and possibly Paraz hijinites guizhouensis (Qian, 1978a; Qian & Yin, 1984b; Wang et aI., 1984a,b) may be synony mous, especially given some co-occurrences in Bed 16 of the Guzhongwu section, Zhi jin County (Wang et aI., 1984a,b). Many zhijinitid taxa from
Wider affinities ofCambroclavus and Zhijinites. Mambetov & Repina (1979) commented on the similarities of cambroclaves to conodonts, such as Protohertzina and Hertzin a, but our study provides no supporting evidence. Qian (1978a) drew comparisons between Zhijinites, Fom itchella and lapworthellids, but later he drew other and more detailed comparisons between Zhi jinites and the recurved proboscis hooks of the endoparasitic acanthocephalans (Qian & Yin,1984b; Qian & Xiao, 1984, p. 79), arguing that they represented an ancestral group. Even if the spines had a grasping function, there is little evidence to support comparison with the un mineralized hooks of acanthocephalans. Deriva t i o n of Cambroclavus f r o m Zhijinites a n d corresponding development o f a n articulated scleritome adds little support. Few data are available for a firm assessment of cambroclave affinities. The mode of secretion differed markedly from other Lower Cambrian animals with a scleritome, such as coelosclerito phorans or tommotiids. Derivation from a turbel larian-like ancestor seems possible, but if so, acquisition of skeletal structures was probably independent of other evolutionary lines. Stratigraphy
Fig. 74. LapworthellaJasciculata Conway Morris & Bengtson, sp. novo Horse Gully, Parara Lst., UNEL1852 (A), UNEL1854 (B-E), UNEL1856 (F-Q). A, SAMP30613, x60. B-E,.holotype, SAMP30614. B, x60. C, apical region, x200. D, x60. E, ornamentation, x200. F,G, SAMP30615. F , x60. G, apertural view showing occluding septum, x60. H, SAMP30616, apertural view, x60. I,J, SAMP30617. I, x60. J, apical region showing transverse septum, x200. K, SAMP30618, interior showing incomplete septa, x60. L, SAMP30619, longitudinal section showing sepIa, x40. M-O, SAMP30620. M,N, ornamentation, x60. 0, x40. P, SAMP30621, x60. SAMP30622, x40.
Q,
EARLY CAMBRIAN FOSSILS, S. AUST.
117
118
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
119
Cambroclavus in Kazakhstan (Mambetov & 'eva,1981), although incorporation of Cerabo Repina,1979) and Hubei (Qian & Zhang, 1983) nusoides (Qian, 1978a) is regarded as dubious. with Rhombocorniculum cancellatum indicates To Landing's (1984) assignments should be a middle to upper Atdabanian age (Mambetov & added Lugoviella Grigor'eva in Grigor'eva, Repina, 1979, fig.7). Reports from Xinjiang, Melnikova & Pelman, 1983, and 'Tommotia' (Qian & Xiao, 1984; Qian & Yin, 1984b) and jinshaensis Yuan & Zhang, 1983, which is Australia are consistent with this age. Australian similar to Sonella (cf. Bengtson, 1986a). cambroclaves appear near the top of the Parara The Tommotiidae contains Camenella Mis Lst. at Horse Gully and Ajax Lst. in the Mt. Scott sarzhevsky in Rozanov & Missarzhevsky, 1966, Ra. Trilobites occur either in association with or sensu Bengtson, 1970 (=Tommotia Missar in strata below the cambroclaves, but in zhevsky, 1970), Dailyatia Bischoff, 1976, and Kazakhstari and Xinjiang, trilobites appear to be . tentatively Ninella Missarzhevsky in Missar locally absent (Mambetov & Repina, 1979; Qian zhevsky & Mambetov, 1981), but Landing's (1984) inclusion of Eccentrotheca Landing et & Xiao, 1984). However, in Fangxian, Hubei Province, co-occurring material referred to as al., 1980, is regarded as provisional (Bengtson, gen. et sp. indet. by Qian & Zhang (1983, pI. 2, 1986). figs 11-14) is probably trilobitic. To the Tannuolinidae are allocated Tannuolina Substantially younger cambroclaves occur on Fonin & Smirnova, 1967, and Micrina Laurie, Hainan Island (Jiang & Huang, 1986), where 1986, while the Sunnaginiidae contains only associated trilobites (Sun, 1963; Zhu & Lin, Sunnaginia Missarzhevsky in Rozanov et al., 1969. Laurie (1986)erected the Kennardjidae for 1978) indicate a roughly Ordian age. This inter y,al was regarded as basal Middle Cambrian by Kennardia Laurie, 1986, to which family he also provisionally assigned Dailyatia; Finally, al Opik (1967), although in terms of the American though Paterimitra Laurie, 1986, is obviously a (Palmer, 1977) and Soviet (Spizharski et al., tommotiid, its familial positi on is uncer 1986) schemes an up'per Lower Cambrian age tain. Tommotiids appear. to be most charac-: seems more likely (Opik, 1975b fig.3; Kruse, 1987). Although Opik (1975a) regarded the ini teristic ofthe Tommotian andAtdabanian stages, tial report by Sun (1963) as inconclusive with but at least one species of Lapworthella may range into the Middle Cambrian of Bornholm regard to an Ordian (or Templetonian) age, it (Poulsen, 1942; Berg-Madsen, 1981) .. now se-ems accepted that the section in Hainan Island is Ordian. Eccentrotheca Landing et al., 1980 [SB]
. TOMMOTIIDS [SCM] Tommotiids are conical phosphatic sclerites which grew by internal, basal secretion. For clas sification we follow Landing (1984; see also' Bengtson, 1986; Conway Morris & Chen, 1990b),;who recognized four families. The Lapworthellidae include Lapworthella Cob bold, 1921 (?=Stenothecopsis Cobbold, 1935), Kelanella Missarzhevsky in Rozanov & Missarzhevsky, 1966 (?=Bengtsonia Missar zhevsky & Grigor'eva, 1981;both genera placed in Kelanellidae by Missarzhevsky & Grigor' eva, 19 8 1) , Bercutia M i s s a r z h e v s ky i n M i s sarzhevsky & Mambetov, 1981 (?=Geresia Mis sarzhevsky in Missarzhevsky & Mambetov, 1981), and Sonella Missarzhevsky & Grigor'e va, 1981 (?=Tesella Missarzhevsky & Grigor-
1980
Eccentrotheca Landing et al., p. 404.
Type species. Eccentrotheca kanesia Landing, Nowlan & Fletcher, 1980 from the Callavia Zone in the Little Hollow Formation, Nova' Scotia. Other species. Eccentrotheca grandis Brasier, 1986b; E. guano sp. nov. Diagnosis. Highly variable, densely laminated, phosphatic sclerites ranging in shape from nar rowly to broadly conical. Sclerites usually flat tened with marginal or strongly eccentric apex that produces right and left symmetry variants. External markings of sclerites restricted to coarse growth lines. (Modified from Landing et . -al., 1980.)
Fig. 75. Lapworthella fasciculata Conway Morris & Bengtson-, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1867 (A), UNEL1872 (I,J), UNEL1873 (C-H, M); Horse Gully, Parara Lst., 6429RSI05 (B), UNEL1856 (K,L). A, SAMP30623, x60. B, SAMP30624, x90. C, SAMP30625, x120. D, SAMP30626, x120. E, SAMP30627, x60. F, SAMP30628, x120. G,H, SAMP30629. G, x120. H, ornamentation, x400. I,J, SAMP30630. I, x40. J, ornamentation and growth ridges, x120. K,L, SAMP30631. K, longitudinal section (polished) showing septa, x60. L, specimen prior to sectioning, x40. M, SAMP30632, x60. -
.
120
STEFAN BENGTSON et al.
EccentrQtheca guano Bengtson, sp. nov. (Figs 71-73) Eccentrotheca cf. kanesia Landing et al.; 1986 Laurie, p.446, fig. 9A-E.
Etymology. Spanish guano, referring to the exos keleton as a fairly unstructured phosphatic crust. Material. Holotype S AMP30596 (Fig. 71H) from 6429RS103, Horse Gully, Kulpara Lst. c. 3.5m below top; c. 60 paratypes. Distribution. Horse Gully, Kulpara and Parara Lsts, 642 9RS 103 -104, U NEL1856,1857); Amadeus Basin, Todd River Dolomite (Laurie, 1986). Diagnosis. Sclerites highly va riable, from tubular to conical to flattened triangular. Most sclerites flattened, with variable curvature per pendicular to plane of flattening. Curvature in the plane of flattening may also occur. Initial deposit conical to crescentic, subsequent angle of lateral divergence 0-80°. Adjacent sclerites commonly fuse during growth. Occasional growth reces sions of sclerites. Descri ption. Sclerites are basically cone-shaped, growing by accretion of calcium phosphate around the whole periphery from a primordium which may be rounded cap-shaped (Fig. 71J,0, Q,R,W), but usually is laterally elongated (Fig. 71A,B,F,G,I,K,�,S,U). Growth lines are char acteristically coarse and irregular suggesting that morphogenesis was rather 'sloppy' and disor ganized. The most common shape is a broad, flattened cone (Fig.71A,B,I,K), butall gradations through narrow flattened (Fig. 71J,L) or less flattened (Fig. 71C,P) cones to t:tJbular flattened (Fig.711) or non-flattened (Fig.710) forms with parallel sides are found. The sclerites may be nearly flat (Fig. 71U), but are usually curved towards one of the flattened sides (Fig. 71A,B,F,G,H,I,M, S,T). There is commonly also an asymmetrical curvature in the plane of flattening (Fig. 71A,B,
J,V).
Characteristic of Eccentrotheca, and in par ticular this species, is a tendency of sc1erites to merge during growth, so that multiple tips are formed (Figs 71D,F,H,N,S, T,U,W, 72). Such fusion could occur laterally (Fig. 71D, N,S,T,U) or between the broad sides of sclerites (Figs 71F,H, 72). Some sclerites show a constriction, suggesting that the secretory tissue was reduced in extent during sclerite growth (Fig. 71G). Others show more extreme growth irregularities (Fig. 71W). The inner surface is finely granular to pitted (Fig. 72).
One large specimen (Fig. 73) is only ques tionably referred to E. guano. It appears to rep resent strong expansion and change in growth direction from an initially flattened triangular sc1erite. Since its growth mode is quite distinct, the specimen is not included in the type series. Remarks. Sclerites of Eccentrotheca evidently were parts of a composite exoskeleton. The ex treme shape variation and often very narrow internal cavity make it very unlikely that each sclerite served to house an individual. More im portantly, the frequent merging of adjacent sc1erites into larger complexes speaks against any such notion (Landing, 1984). This phe nomenon was found by Landing (1984, 1988) in E. kanesia a n d Lapworthella schodackensis (Lochman, 1956), the latter considered on grounds identical to those cited above for Ec centrotheca to have had a composite scleritome (Bengtson, 1977; Landing, 1984). Sclerite merg ing in tommotiids has been observed in Lapwor thelia cornu (Wiman, 1903) (Hinz, 1987; specimens belonging to her Lapworthella Mor photype A) and Tannuolina zhangwentangi Qian & Bengtson, 1989. Eccentrotheca, p a rticularly E. g uano, is remarkable on account of its low degree of mor phogenetic control in skeletogenesis. The animal may be envisaged as having had an irregular body surface on which mineralized tissue was deposited from unevenly distributed secretion centres. During growth the edges of adjacent skeletal units sometimes came into contact and merged, but there was no coalescence of larger units. The net effect was to produce a tough but flexibly imbricating scleritome of calcium phosphate. These sclerites are recognized by the crude pattern of growth lines and a tendency to form flattened sclerites with a triangular outline. To identify species it is necessary to have an as semblage of sclerites, that will show the pattern of variability. Individual sc1erites of E. kanesia may be indistinguishable from those ofE. guano. Landing et al., (1980) and Landing (1988) described associations of E. kanesia sclerites, varying continuously from conical, flattened, symmetrical or asymmetrical sc1erites to low, broad plates with the concave side reduced to a duplicature. The last type of plate is poorly rep resented in the E. guano assemblage, although one could possibly identify a duplicature in one specimen (Fig. 72). Conversely, E. kanesia as semblages seem to lack the narrow conical forms typical of E. guano, and the merging of sclerites appears to be less frequent in the former. For this reason the holotype (Fig. 71H) was selected to represent a merger between a narrowly conical and a broader triangular sclerite.
EARLY CAMBRIAN FOSSILS, S. AUST.
121
Fig. 76. Lapworthella Jasciculata Conway Morris & Bengtson, sp. novo Mt. Scot! Ra., Ajax Lst., UNEL1872. A, SAMP30633, aperturai view showing septa, x20. B, SAMP30634, x90. C,D, SAMP30635. C, junction between septum and inner wall, x200. D, oblique view showing septum, x60. E-G, SAMP30636, x60. H, SAMP30637, ornamentation, x60. I, SAMP30638, x60. J,K, SAMP30639, ornamentation and growth ridges, x200.
Family LAPWORTHELLIDAE Missarzhev sky, 1966 [SCM, SB]
Lapworthella Cobbold, 1921 *1921 Lapworthella Cobboid, p.359.
?* 1935 Stenothecopsis Cobboid, p.43 [see Pouisen, 1942, p.228; Lochman, 1956, p.1394].
Type species. L. nigra Cobbold, 1921, from the Comley Lst. of Shropshire. Other species. Many of the nominal species are listed by Conway Morris & Fritz (1984), Qian & Bengston (1989) and Conway Morris & Chen (1990b). The taxonL. zhangshanensis (Yin et al., 1982, pp. 287, 291; Wang et al., 1984a, p.105, tables 5.2, 5.3) appears to be a nomen nudum. L. honorabilis (Qian et al., 1979, p.219, p1.3, figs
122
STEFAN BENGTSON et al.
1,4) is not accepted as 'a lapworthellid, and ap pears to represent monoplacophoran steinkems (Conway Morris & Fritz, 1984, p.204), as does L. orientalis (Yin et al., 1980, p.174, pI. 17, figs. 17-19; see also Xing et al., 1984b, pI. 14, fig. 15). However, material identified by Chen & Zhang (1980, pI. 2, fig. 21) may not be com parable and is questionably assigned to Lapwor thelia. Material referred by Yin et al. (1980) to Lapworthella sp. (their p. 174, pI.17, figs 21-23) and Lapworthella ?sp. (their pl.l7, fig.20) ap pears to represent annulated tubes. The query raised by Conway Morris & Fritz (1984, p.198) tl)at L. rostriptutea (misspelt in Qian et al., 1979. rostriplutea (pp.209, 210,219,228), stripleteus (p.210) and rostriplulea (p.233», was a nomen nudum is incorrect, as they had overlooked a description given by Qian (1978b, p.137, pl.15, figs 1,2a,b). However, it cannot be referred to L.apworthella, placophoran steinkerns. The status of material referred to L. cf. nigra from southwest Sichuan (Zhong [Chen], 1977, pl.4, figs 18,19) is uncer tain.
Distribution. Lower Cambrian of Siberia, China (Hubei, Sichuan, Yunnan), United States (New York), Canada (Newfoundland, British Colum b ia), En gland, Sweden, Aus tralia (South Australia), and Middle Cambrian of Bornholm (Denmark). Diagnosis. More or less conical sclerite with circular to quadrangular cross section, usually some longitudinal torsion. Externally oma mented with ridges separated by inter-ridge areas, either region may be smooth or .bear tubercles, spines,ribs or other scu1pture. Internal cavity may be septate. Original composition phosphatic, growth by basal-internal secretion of thin lamellae.
L. dentata Missarzhevsky in Rozanov et al., 1969 is a junior synonym of L. shodackensis Lochman, 1956 (Landing, 1984); L. lata Mesh kova in Repina et al., 1974, L. corniformis Mesh kova, 1969, and L. marginata Meshkova, 1969, are junior synonyms of L. bella Missarzhevsky, 1966; L. bornholmiensis, L. cobboldi, L. quad rangularis a n d L. subtriangularis (Poulsen, 1942) are synonymous (Berg-Madsen, 1981, p.226); L. ablorta, L. sinensis and L. subrectan gulata (Duan, 1984) appear to be synonymous and may be co-specific with some specimens of L. annulata (Qian & Yin, 1984a); while L. can cellata (Jiang in Luo et al., 1982) may be synonymous with L. gezhongwuensis (Qian & Yin, 1984a; N.B. same specimen illustrated asL. orientalis(misspelt orentalis on p. 246) by Wang et aI., 1984b, p.93, p1.21, fig.3, see also p.132 where it is referred to as L.? orientatus [sic]). In other cases allocation to existing species is inap� propriate. For example, specimens that Jiang (in Luo et al., 1982) referred to L. bella (his p1.18, fig.4), L. cf. cornu (his pl.l8, fig.6), L. marginata (his pl.18, fig.7), L. cf. nigra (his pI.18, fig.8), and L. tortuosa (his p1.18, figs 1,2) are all er roneous identifications, and in the majority of cases cannot be definitely referred to L apwo r thelia. Lapworthella fasciculata Conway Morris & Bengtson, sp. novo (Figs 74--76) Etymology: From the prominent longitudinal fas ciculae on inter-rib areas. Material. Holotype SAMP30614 (Fig. 74B-E), Parara Lst., UNEL1854,. Horse Gully; 26 figured paratypes; c. 100 other paratypes. Distribution. H o r s e Gul l y , P a r a r a Lst. (6429RSI13, UNELI852-1854, 1856, 6429RS105); Mt. Scott Ra., Ajax Lst. (UNELI8661868, 1871-1874, 1876, 1877).
Comparisons. Stenothecopsis (type S. heraul tensis Cobbold,1935) may be synonymous with Lapworthella, but the type material is misplaced. Diagnosis. Elongate sclerites of variable shape, ranging from cornute to pyramidal. External or The morphological complexity of lapworthellid sclerites which involves characters such as rela- . namentation of well-developed growth ridges and inter-ridge areas, the latter with prominent tive strength and ornamentation of growth ridges and sculpture of inter-ridge areas, has facilitated longitudinal ribs that impart a fasciculate ap pearance, somtimes continuous over several species recognition, but a striking degree of ridge-inter-ridge intervals. Intersection of ribs variation (Matthews,1973; Hinz, 1987) means that the distinction between some species is not and growth ridges gives latter no dose ap pearance. Apertural shape variable, sub-circular well founded. Hinz (1987) made far-reaching proposals that the majority of lapworthellid to quadrangular. Internally sclerite septate, con cave aperturally. species are synonymous and merely variants of sclerites from a highly variable scleritome. While such an approach should be received sym Description. Cornute to pyramidal in shape, with pathetically, the lack of adequate descriptions of variable degree of coiling. Apertural outline may be subcircular (Fig.74D,Q), triangular or quadvariation makes judgement premature.
E ARLY CAMBR I AN F O SSILS, S. AUST.
123
Fig. 77. Lapworthella cf.fasciculata Conway Morris & Bengtson, sp. novo Curramulka, Parara Lst., UNEL1846 (A-L,O), UNEL1847 (P,Q); Kulpara, Parara Lst., 6529R S104 (M,N). All x120 except 0 and Q (x200). A, SAMP30640. B, SAMP30641. C, SAMP30642. D, SAMP30643. E, SAMP30644. F, SAMP30645. G, SAMP30646. H, SAMP30647. I, SAMP3064 8. 1,0, SAMP30649. K, SAMP30650. L, SAMP30651. M,N, SAMP30652. P,Q, SAMP30653.
rate (Fig.74G,P). The adapical end is a simple short cone without conspicuous ornamentation (Figs 74C, 75B,F,G,M, 76B). External ornamentation is prominent, con sisting of growth ridges that form buttress-like
extensions, separating inter-ridge areas bearing closely spaced longitudinal ribs that are smooth and have a semicircular cross-section (Figs 74E,M, 75J, 76H). These ribs usually occur over several inter-ridge divisions (Figs 74N, 76J,K),
124
STEFAN BENGTSON
et al.
sometimes for greater distances. The strength of ribbing varies, and may' 74F,P) to prominent (Fig. 76H;J, K). Even within individual sclerites the degree of development is variable so that prominent ribs may be inter spersed with more subdued structures. Spacing of the growth ridges (Fig.74E) is relatively con stant, although these major ridges may be separated by much more subdued transverse welts. The bluntly dentate pattern of the growth ridges results from intersection with the lon gitudinal ribs. Sclerite walls are thin (c. 25 t-tm), with lamellar growth by basal-internal accretion. The internal cavity is subdivided by thin-walled septa, con cave aperturally (Figs 74J-L,P, 75K, 76C,D), that show a rather irregular spacing not directly corresponding with the external' growth ridges. Eachseptum formed by retraction of the secretory tissue, in a manner analagous to septal formation in groups such as cephalopods, hyoliths and teritaculitids. On the adapical side adjacent to the main wall the septum 11;1ay show narrow radial.walls (Fig. 76C), possibly to strengthen the septum. Comparisons. Comparison of L. Jasciculata with the numerous nominal species of Lapworthella published elsewhere is difficult for reasons given above. Notwithstanding these problems, L. Jas ciculata.has certain similarities to a number of otner species. In . particular L. bornho"lmiensis {Poulsen,1942) from the Middle Cambrian Ex s'ulans Lst. (Kalby and Borregard Members) and j?v'edying Angrarum LsL (Berg-Madsen, 1981, -1985) has a comparable fasciculate pattern of "inter-ridge ribs extending a considerable distance along the sclerite generating a nodose pat ter n as they c ross the growth ridge s. L. bornhOlmiensis differs from L. Jasciculata in having broader and more subdued ribs, less prominent growth ridges. Sectioned material of L. bornholmiensis failed to reveal internal septa. Similarities exist with L. cancellata from the Dahai Member of the Meishucunian of Yunnan (Jiang in Luo et aI. , 1982, pl.18, figs 3, 3a, text-fig.56; Xing et al. , 1984b, pl.l0, fig. 22), although the longitudinal ribs of the latter may show greater continuity. .' Relatively prominent ribs are characteristic also of L. ludvigseni, but the adventitious septa are of a greater thickness than those of L. fasci_
culata, and the growth ridges have low relief and are much more frequently spaced. Landing (1984) suggested that fossils identified asL. tor tuosa from the Meischucunian (Jiang in Luo et al. , 1982, pl.18, figs 1,2) were synonymous with L. ludvigseni, but this suggestion is provisional. With regard to- other species of Lapworthella, L. fasciculata shows only generalized simi larities, although as explained below the mor phological differences between species may be only a' result of minor changes in various secretory modes.
Lapworthella cf. fasciculata Conway Morris & Bengtson, sp. novo (Figs 77,78)
Material. Twenty-two figured specimenS from ?UNEL1845, 1846, 1847, I763B, Parara Lst. at Curramulka and 6529RSI04, Parara Lst. at Kul para.
j
Diagnosis. Sclerites small, conical, with aper tural shape subcircular to oval. Growth ridges with irregular tuberculate ornamentation on outer edges, otherwise more or less smooth. Inter-ridge areas with irregular ornamentation of subdued tubercles or occasionally subdued lon gitudinal ribs. Adapical region a slender cone bearing irregularly disposed tubercles. Description. Sclerites are small, seldom longer than c. 800J..Lm, broadly conical to almost tubular, with an oval to rounded apertural outline. The apical area is a finely tapering cone, with a smooth terminus succeeded by a zone bearing adapically directed elongate tubercles (Figs 77Q, 78A,B,C,F,J,K). Their density of spacing is vari able, but even where closely packed they never form a regular arrangement. The rest of the ex terior bears generaJ1y prominent but relatively narrow growth ridges with variable separation. The outer margin is irregularly dentate, with strength of denticulation varying from almost smooth (Figs 77C,K, 78L) to ridges with con spicuous teeth (Figs 770, 78W). Away from th e margin the remainder of the growth ridges may bear weakly d evelo ped and irregular lon gitudinal folds (Fig. 77G,K). Inter-ridge areas are relative1y smooth, apart from sparse tubercles (Figs 77D, 78Q,S,W), and sometimes rather ir regular longitudinal welts (Fig.77J), organized
Fig. 78. Lapworthella cf.Jasciculata Conway Morris & Bengtson, sp. nov. Curramulka_, A-D, SAMP30655. A, x60. B, apex, x200. C, apex, x200. D, growth ridges, x200. E, SAMP30656, x120. F,G, SAMP30657. F, apex, x400. G, x120. H-K, SAMP30658. H, x60. 1, growth ridge, x400. J,K, apex, x200. L-O, SAMP30659. L, x120. M, x120. N, x60. 0, x60. P,Q, SAMP30660. P, x60. Q, growth ridges and inter-ridge areas, x200. R-U, SAMP30661. R, x120. S, growth ridges and inter- ridge areas, x400. T, x120. U, apex, x400. V,W, SAMP30662. V, x120. W, growth ridges and inter-ridge areas, x400.
EARLY CAMBRIAN FOSSILS, S. AUST.
125
126
STEFAN BE NGTSON et al.
Fig. 79. Lapworthella puttapensis Bengtson & Conway Morris, sp. novo Puttapa, Ajax Lst., AUS76-5-1, coli. A. Martinsson. A-D, holotype, SAMP30663. A, x140. B, ridges and inter-ridges, x450. C, apical region, x600. D, ridge, x1500. E,F, SAMP30664. E, x140. F, ridge, x1500.
EARL Y CAMBRIAN FOSSILS, S. AUST.
127
Fig. 80. ?Lapworthella sp. A., SAMP30665. Curramulka, Parara Lst., UNEL1846. A, x200. B, apical region, x900. C, abapical region, x900.
into fasciculae (Fig. 77M,N). Internally, the sclerite walls were smooth, and septa absent. Comparisons. The virtual restriction of this form to the Parara Lst. at Curramulka could support specific differentiation from L. Jasciculata. Al though the apex of the latter is seldom preserved, the available specimens (e.g. Fig. 74C) lack tuberculate apices. Moreover, rate of sclerite ex pansion of L. Jasciculata is greater, making it unlikely that these sclerites are simply detached portions. Ornamentation also differs, and the fas ciculae are seldom as strongly developed. How ever, because specimens from the Parara Lst. at Kulpara (6529RS104) show joint possession of prominent fascicles and a tuberculate apex (Fig. 77M,N), this form is tentatively retained in L. fasciculata. These sclerites also exhibit some similarities with other species. L. lucida (Meshkova, 1969; Meshkova in Repina et aI., 1974) has a tubercu late apex succeeded by weakly dentate growth ridges, but differs in also having strongly tuber culate inter-ridge areas. Apical tuberculation is characteristic also of morph B of L. f iligrana (Conway Morris & Fritz, 1984), and has been noted on occasional specimens of L. schodack ensis (Landing, 1984, fig.2H). Moreover, in
Siberian species such asL. tortuosa andL. bella, a similar zone with tubercles may be present, but is repeated serially along the rest of the sclerite (Missarzhevsky in Rozanov & Missarzhevsky, 1966; Rozanov et aI., 1969; Meshkova, 1969; Meshkova in Repina et al. , 1974). Lapworthella puttapensis Bengtson & Con way Morris, sp. novo (Fig. 79)
Etymology. From the locality Puttapa, South Australia. Material. Holotype SAMP30663 (Fig. 79A-D) from Puttapa M ine, 16km north of Beltana, South Australia (locality 21 of Thomson et al., 1976; Ajax Lst., collected by A. Martinsson in 1975); one paratype. D ia gnosis. Cornute sclerites; prominent growth ridges with tuberculate ornamentation, espe cially on abapical sides of each ridge; inter-ridge areas generally narrow. Description. Although known from only two specimens from one sample, its highly distinc tive morphology in comparison with other Australian lapworthellids warrants description.
128
STEFAN BENGTSON et al.
Table 2. Lapworthellid growth codes. Code:Secrete continuously in an abapical direction togenerate inter-ridge zone Secrete in a lateral direction to generate a growth ridge' Secrete tubercles Secrete longitudinal ribs Repeat sequences
R (for run) S (for stop) T B
Codes for lapworthellid species
L. tortuosa
R, RT,! or R, RT, ST, R!
Description. This unique specimen fonns a gent ly recurved and elongate cone (c. 0.5mm long). The apex is missing, but the initial section bears irregularly distributed scales (Fig. 80B). Abapi cally their spacing increases until ultimately they form very irregular concentric rings linked by a reticulate network (Fig. 80C). The aperture of the cone is somewhat oval, delimited by a smoother zone. The apical region is reminiscent of the same zone in L. cf. fasciculata, but the reticulate pat tern with ill-defined growth ridges d iffers markedly. Although this sclerite could have been derived from the same scleritome, it is prudent to retain it under open nomenclature until more material becomes available. Functional morphology of lapworthellids
L. bella L. cornu L. schodackensis L. lucida L. puttapensis L. bQrnholmiensis L. Jasdculata L. ludvigseni
R, ST! R, ST! R, ST! RT, ST, S, RT! RT,ST! RB, SB! RB, SB! RB, SB!
Sclerites are cornute, expanding rapidly (Fig. 79A�E). .The spinose apex is smooth, although the termination may not to be preserved (Fig. 79C). The remainder of each sclerite bears a prominent series of rounded growth-ridges (Fig. 79B), closely spaced so that the inter-ridge areas are reduced, especially· towards the aperture. The growth ridges bear abundant tubercles, bluntly terminating (Fig. 79D,F), and apparently dis posed in obliquely inclined rows. These tubercu late zones grade adapically into somewhat smoother regions, sufficiently broad to define inter-ridge areas. It is not known whether the internal cavity was septate. Comparisons. The distinctiveness of L. put tapensis makes comparisons difficult. The tuber culate ornamentation recalls the pattern in L. lucida (Meshkova, 1969; Meshkova in Repina et al., 1974), but in general similarities are not striking.
?Lapworthella sp. A (Fig. 80)
Material. On e f i g u r e d s p e c i men UNEL1846, Parara Lst., Curramulka.
from
If lapworthellids were epifaunal, primary scleri tome function may have been protection. Except for evidence from fused sclerites (Landing, 1984; Hinz, 1987), however, their disposition is speCUlative. Septa in lapworthellids are uncom mon. In L. ludvigseni from the probable At dabanian of the Avalon Zone (southeast Newfoundland and Massachusetts) they were· described by Landing (1984) as 'adventitious', because of their apparently irregular appearance. In L. fasciculata, however,· septa appear to be common, possibly invariable. Landing (1984) argued that septa were a response to phosphate conservation during skeletogenesis. This sug gestion, although plausible, raises the question why septa were not employed more widely in otherlapworthellids, although comparable struc tures are known in other tommotiids. Recognition of lapworthellid species Interpretations of lapworthellid relationships depend largely on ornamentation patterns, al though as stressed above such critical data too often are either obscure or wanting. The difficul ty in deciding the morphological ranges of some species (Hi nz, 1987) is exemplified in the discus sion of whether L. fasciculata and L. cf. fas ciculata should be separated. As with other scleritome-bearing metazoans, single sc1erites may be unrepresentative, especially when they fortuitously approach other species. Not withstanding the apparently bewildering array of lapworthellid m orphologies, t abulation of growth sequences by a few simple 'commands' consisting of basic instructions to secrete either
Fig. 81. Camenella reticulosa Conway Morris, sp. nov., sellate sc1erite (L-fonn), holotype, SAMP30666. Horse Gully, Parara Lst., UNEL1856. A, x40. B, x40. C, x40. D, x40. E, growth ridge, x600. F, growth ridges, x200. G, growth ridges, x90.
EARLY CAMBRIAN FOSSILS, S. AUST.
129
130
STEFAN BENGTSON et al.
Fig. 82. Camenella reticulosa Conway Morris, sp. nov., mitral sclerites. Horse Gully, Parara Lst., UNEL1856. A-E, SAMP30667. A, plicate side, x40. B, accrescentplicate side, x40. C, plicate side, x40. D, accrescent side, x40. E, a pical view, x40. F,G, SAMP30668. F, inner side, x60. G, part of plicate side, x60.
laterally (ridges) or abapically (inter-ridges), together with f ormation of tubercles or ribs (Table 2) will account for all the basic patterns. Combinations of such growth codes can specify particular species, with species sharing the same code distinguished on other criteria, e.g., denticle spacing. For example; the two groupsL. bell a/L. shodackensis (and the either synonymous or closely relatedL. dentata, L. lata, L. corniformis and L. m arginata) and L. bornholmiensis/L. fasciculata/L. ludvigseni each have a shared code (R, ST! and RB, SB ! respectively), but are distinguished on other points. Such analyses reveal how dif ferent species (or populatiOIis) could generate seemingly different patterns by possibly trivial changes in secretory activity (Hinz, 1987). Using growth codes may lead to improved understanding of species transitions,
but it also indicates the potential ease of parallel evolution. Are there any excluded combina tions? Present indications are that almost any combination may occur.
Lapworthellids as tommotiids In addition to Lapworthella itself, the Lapwor thellidae comprise Kelanella, Bercutia, and Sonella (and various synonyms). These latter f orms are distinguished by distinctive external ornamentation, but in Kelanella (and Sonella) the presence of septa has also been claimed to be diagnostic. However, septate lapworthellids (L. fasciculata and to a lesser extent L. ludvigseni) suggest that septa were recurrent and probably of little taxonomic significance. Striking similarities may exist between the ex-
EARLY CAMBRIAN FOSSILS, S. AUST.
131
" ternal ornamentation of lapworthellids and other ' (1910, 1977), who provided evidence(Bengtsori, tommotiids. Convergence between L. fa s1986) that the camenellid sc1eritome was ciculata and tommotiids such as Camenella ad- equipped with sellate and m-itral authors (M�shkova in Repina et al., 1974; miranda (Rozanov & MissarZ:hevsky, 1966, pl.13, fig.7; Meshkova, 1969, p1.54, figs 1,2), C. Grigor'eva'-in Voronin et al., 1982; Grigor'eva in baltica (Bengtson,1970),- and C. parilobata Sokolov & Zhuravleva,1983; Fedorov, 1984; Bengtson, 1986a may indicate close relationship Rozanov, 1986) nevertheless persist in separat between these genera. ' ing Tommotia from Camenella. Bengtson (1986) indicated that a number of the described species Family TOMMOTIIDAE Bengtson, 1970 are probably synonymous, but lack of illustrated material and insufficient appreciation of varia[SCM] ' tion preclude any useful speculation. *1969 CAMENIDAE Missarzhevsky in Rozanov et . al., p.165. Camenella reticulosa- Conway Morris, sp. . * 1970 TOMMOTIIDAE Bengtson, p.374. nov: (Figs 81,82) r
Camenella Missarzhevsky in Rozanov et al., 1969
1966
Camena Missarzhevsky in Rozanov & Mis sarzhevsky,
p.93. [non Martens, 1860; Hewitson, 1865] *1966 Camenella Missarzhevsky in Rozanov & Missarzhevsky, p.95. *1970 Tommotia Missarzhevsky, nom. novo p.100. Type species.
Camenella garbowskae M i s
sarzhevsky in Rozanov & Missarzhevsky, 1966.
Other species. Many of the nominal species are
listed by Bengtson (1986, p.47) to which may be added C. parilobata Bengtson, 1986, and C. reticulosa sp. nov. Bengtson (1986) noted that C. korolevi Missarzhevsky in Missarzhevsky & Mambetov, 1981, and probably C. applanata Grigor'eva in Voronin et al., 1982, could not be accommodated in Camenella.· The likely posi tion of T.jinshaensis Yuan'& Zhang, 1983, in the Lapworthellidae was mentioned above.
Etymology. For the reticulate ornainent of the sellate sclerites.
Material. Holotype SAMP30666 (Fig. 81A�G)
.
from UNELI856; 2 figured paratypes and30th�r . speCImens.
Distribution. Horse Gully, Parara Lst. (UNE LI856); Kulpara, Parara Lst. (YNELI860C).
Diagnosis. Sellate sclerites, strongly aSYmmet
rical with prominent sella separating large and small lobes (terminology of Bengtson, 1970, 1986)" with subsidiary fold. Prominent growth ridges bearing reticulate pattern of nodes; inter:.. ridge areas more or less smooth.' Margin· of sclerite bears duplicature, and internally incom� plete septa. Mitral ... sclerites ' acutely' pyramidal w,ith helical component along length,' obplicate facet with single� prominent ridge, growth ridges more or less smooth.
Description. The rarity of this new species makes
it likely that morphological variation is greater Distribution (after Bengtson, 1986). Lower than documented here. Sellate sc1erites (Fjg. 81) Cambrian of Siberian Platform, western Mon are strongly recurved and asymmetrical, with large and srn all lobe separated by prominent sella golia, South Australia, northwest Europe and ) southeastern Newfoundland. At present, records (Fig. 81C,D). The sides of the sella are steep, but their margins with the lobes are not definite from China (Yunnan) seem to be equivocal. Material referred to Camenella sp. by Jiang (in ' ridges. The external surface bears prominent and fairly closely spaced growth ridges whose Luo et al., 1982, p.189, pl.18, figs 12, 13) may deflection on the mature section of the large lobe be c o m p a r e d b e t t e r w i t h Tannuolina. A defines a subsidiary groove (Fig. 81D,G). A specimen identified as C. plana (Jiang in Luo et al., 1984, pl.13, fig. 1,1a) is conceivab1y a mitral much more subdued deflection is also apparent on the small lobe. The growth ridges bear closely sc1erite of a Camenella. Identification of another spaced nodes, separated by a subdued reticula specimen as ?Camenella sp. by Jiang (1980a, p1.2, fig.12; referred to as Camena) is difficult to tion (Fig. 81E,F). Inter-ridge areas appear to have been more or less smooth. The sclerite justify from the available illustration .. margin bears a duplicature, and internally there are incomplete septa. ' Diagnosis. See Bengtson, 1970, p. 374. Mitral sclerites are acutely pyramidal (Fig. Comparisons. The confused taxonomic history 82A,C), with a strongly helical component (Fig. 82E). The plicate facet bears a symmetrical arhas been thoroughly discussed by Bengtson
132
STEFAN BENGTSON et al.
Fig. 83. Kennardia reticulata Laurie, 1986. 70km SE of Alice Springs, Todd River Dolomite, UNELl863a. A, SAMP30669, x40. B, SAMP30670, x40. C,D, SAMP30671, C, x40. D, growth ridges and reticulate ornamen tation, x200. E-G, SAMP30672. E,F, x40. G, reticulate ornamentation, x400. H-J, SAMP30673. H, x40. T, reticulate ornamentation, x200. J, apical view, x40. K, SAMP30674, x60. L, SAMP30675, x40.
rangement oftwo pairs of radial ridges separated by a more prominent furrow (Fig. 82A,G). The obplicate facet bears a single ridge, while decre scent and accrescent (Fig. 82D) sides are rela tively narrow. Growth ridges are prominent and
closely spaced, but in contrast to sell ate sclerites they appear much smoother. Comparisons. Morphological variability in other
species of Camenella (Bengtson, 1970, 1986),
EARLY CAMBRIAN FOSSILS, S. AUST.
133
Fig. 84. Kennardia cf. reticulata Laurie, 1986. Horse Gully, Kuipara Lst., 6429RS103. A, SAMP30676, x135 . B,C, SAMP30677. B, x180. C, x135. combined with the paucity of C. reticulosa makes comparisons tentative. The reticulate pat tern on the growth ridges of sellates, however, appears to be unique. In overall morphology the sellates recall the strongly developed furrow in Camenella sp. (Bengtson, 1970, figAAl, As, Bl) and C. garbowskae Missarzhevsky (in Rozanov & Missarzhevsky, 1966, pU1, figs 4,5; Mis sarzhevsky in Rozanov et al., 1969, pl.5, fig. 1 ; Meshkova in Repina et al., 1974, pU4, figs 5,7; Matthews & Missarzhevsky, 1975, pl.3, fig.20; Grigor'eva in Sokolov & Zhuravleva, 1983, pl.62; fig.5), but differ in lacking strongly developed radial ridges and possibly in having a better defined small lobe. Mitrals approach more or less closely examples from a variety of species, but a larger sample is needed to draw extensive comparisons. Family KENNARDIIDAE Laurie,1986 [SCM, SB] Kennardia Laurie, 1986 1985
gen. novo aff. Dailyatia Laurie & Sh ergo ld p.85.
,
*1986 Kennardia Laurie, p.439.
Type and only species. Kennardia reticulata Laurie, 1986. Distribution. Lower Cambrian of Australia (Northern Territory). Diagnosis. See Laurie, 1986, p. 439. Kennardia reticulata Laurie, 1986 (Fig. 83) Distribution and material. Laurie's (1986) type material comes from near Alice Springs, south west of Santa Teresa Mission (UNEL1863A) and our seven figured specimens are from the Ross River (UNEL1862A); both localities are in the Todd River Dolomite in the Northern Territory. Diagnosis. See Laurie, 1986, pA39. Description. Laurie (1986) detailed three sclerite types (one symm etrical [ form A] and two asym metrical [forms B and Cl). Our material (Fig. 83) has been studied cursorily, and we add little to Laurie's (1986) observations. The striking
134
STEFAN BENGTSON et al.
:
retic�late . ornamentation (Fig. 83D;G,I) recall the imprints in other fossils, e.g. conodonts . and brachiopods, attributed to epithelial cells� The mode of secretion of Kennardia and related tom motiids possessing cl similar reticulate ornamen t ation (Dailyatia,. Paterimitra, Lapworthella rete; Bischoff,1976; Laurie, 1986; Yue, 1987) has not been investigated in detail. Presumably epithelial tissue mantled part of the outside of the sclerite, as well as contributing to basal internal secretion as in other tommotiids.
'-.
Voronin et al., 1982; S. angulata Brasier, 1986b; S. neoimbricata Brasier,1986b; S. parva Brasier, 1986b. Distribution. Lower Cambrian of Siberian Plat form, western Mongolia, England, south-east Newfoundland, Nova Scotia and South Aust ralia. The specimen .identified as Sunnaginia sp. from the Meishucunian ofYunnaIi (Jiang in Luo et aI., 1982, pl.18, fig.11) appears to be Tan nuolina.
Kennardia cf. reticulata Laurie,1986 (Fig. 84)
Diagnosis. See Landing, 1984, p. 1392.
Material. Two figured specimens from the Kul para Lst., in Horse Gully at UNEL1�58 and . 6429RSI03.
Comparisons. Comprehensive documentation of S. imbricata (Missarzhevsky in Rozanov et al., 1969, p1.6, figs 1-4, text-fig. 46a,b; Matthews & Missarzhevsky, 1975, I'Ll, figs 10,11; Sokolov & Zhuravleva, 1983, p1.64, figs s 1,2; Brasier, 1986b, fig.3c) is not yet available, but there is general agreement concerning the morphologi cal variability of this genus (Landing et al.; 1980; Brasier, 1986b; Hinz, 1987). Brasier (1986b) erected S. neoimbricata for similar material from England and proposed S. parva and S. angulata for material from stratigraphically higher units in Nuneaton and ComIey, respectively. Moreover, Brasier transferred the suite of specimens from Nova Scotia (Little Hollow Formation) that Landing et al. (1980, p1.2;figs 1� 13; figs 5�6) had placed in S. imbricata to S. angulata, while similarly aged specimens (top Smith Point Lst. to lower Brigus Formation) from southeast Newfoundland that Bengtson & Fletcher (1983, fig. 3F,G) had referred to S. cf. imbricata were placed· in S. parva.These reassignments were refuted by Landing (1988). The specific status of S. acuta, of apparently Botomian age, is uncer tain because only a single specimen has been illustrated (Grigor'eva inVoronin et al., 1982, p1.6, fig.l).· Whatever relationships exist be tween the five nominal species of Sunnaginia (Hinz, 1987, p.84), this genus has an extensive stratigraphic range.
Description. Sclerites are conical, showing vary ing· curvature and torsion. Transverse sections range from flattened oval (Fig. 84B) to subtrian gular,·. even subrounded (Fig. 84A). The apex may be·· simple, but in · one specimen forms a tubular extension. offset from the main growth axis (Fig. 84A). External ornamentation consists of strongly developed asymmetric growth ridges. Typically .the ridges· have a scalloped edge, and ott their·. upper and lower surfaces a prominent reticu ; late pattern. on the· crests. Reticulation may extend across some of the inter-ridge area, but at least part is more or less smooth. Comparisons. These fossils resemble fairly closely.K. reticulata, differing in that none of the few specimens is assignable to any of the sclerite types· (A-C) recognized by Laurie (1986). Growth ridges seem more irregular; and the reticulation does not coverthe entire inter-ridge areas (cf. Laurie, 1986, fig. 8F-H). '
Family SUNNAGINIIDAE Landing, 1984 [SCM} �,
Sunnaginia Missarzhevsky. in Rozanov et al., 1969 Type species. Sunnaginia imbricata sarzhevsky in Rozanov et al., 1969.
M i s
Other nominal species . S. acuta Grigor' eva in
v
Sunnaginia sp. nov. A (Fig. 85) Material and distribution. S e v e n f i gured specimens from the Sellick Hill Formation (Cooper sample 32) and Fork Tree Lst. (Cooper
Fig. . 85. Sunnaginia sp. Sellick Hill, Fork Tree Lst, Cooper Collection, Sample 37 (A-K,N,O), Sample 39 (L,M). A,B, SAMP30678. A, upper view, x60. B, lateral view, x60. C,D, SAMP30679. C, upper view, x60. D, anterior view, x60. E-G, SAMP30680. E, upper view; x60. F, lateral view, x60. G, lateral view, x60. H, SAMP30681, upper view, x60. I-K, SAMP30682. I, lower view, x60. J, internal wall showing polygonal ultrastructure, x600 .. ,K, polygonal ultrastructure, x1000. L;M, SAMP30683. L, lower view, x40. M, wall structure, x200. N,O, SA.MP30684. N, upper view, x60. 0, lateral view, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
135
STEFAN BENGTSON et al.
136
l,
samples 37 ,and 39) on the Sellick Hill Main , Diagnosis. More or less triangular sClerites. Left South Road, Fleurieu �eninsula. and right variants, each with one external face (SI) steep to very steep, other two faces (S2 and Description. A wide range '6f variation is based S3) less steep.LobeL2 typically more elongate on asymmetrical" (right and left) plates with a ' thanL1, and L3 bears prominent rostrum. Exter nally growth lamellae generally prominent, quadriradiate outline (Fig. 85A,C,H,N) defined by four lobes, the two sets of which are separated sometimes becoming nodular, especially on L2. Apertural margins typically re�urved, especially by a distinct sulcus on side 4 (S4; see Landing et al., 1980, for terminology). In this material the on L3. Interior more or less smooth, but internal opposite side (S2) also is typically indented, cavity divided by septate divisions� imparting cl dumb-bell shape to the sclerite (Fig. Kulparina rostrata Conway Morris & Bengt 85N). Anterior lobes L1 and L2 are variably differen�iated, but Lt sometimes is rostrate (Fig. son, Spa novo (Figs 86-91) 85E), giving an arched margin'. Posterior lobes L3 andlA are also variably developed. This area, ,Etymology. For the diagnostic rostrum on L3. typically larger than the anterior zone, is defined by constrictions on S2 and S4 (Fig. 85C,E,H,N). Material. Holotype SAMP30698 (Figs, 88F, However, sometimes this constriction' is more 90A-H) from UNELI858, Horse Gul1y, Kulpara medially placed, and anterior and posterior zones, Lst.; 18 figured paratypes, and about 20 addition are then sub-equal (Fig. 85A). The apical zone is ' �l specimens. Also occurs at 6429RS103-105, Kulpara Lst., Horse Gully. ' r�strjcted, and externally· growth lamellae are relatively well defined. The smooth interior is in at teast some' sc1erites demonstrably a septum Diagnosis. As for the genus. (Fig. '8SL). On,the inner wall of one,specimen a patCh�pf reticulate ornamentation (Fig. 85J�K) Description. The phosphatic sclerites resemble' recalls the pattern of other tommotiids (Laurie, co-occurring Eccentrotheca guano, Dailyatia 1986), anc\ may represent an epithelial imprint. ajax and f(ennardia cf. reticulata. In plan view Hinz (1987, pl.9, fig: 10) reported this feature in they are triangular (Fig. 87G, 88B,G, 89C,I, Sunnaginia from Comley, England, where each 90F), defined by three spurs or lobes (L1, L2, L3) and intervening faces or sides, (S" S2, S3) polygon is about the'same size (c. 8-10f.Lm). , (Fig.91). (Note that this terminology does not imply direct homology with the similar formula (;omparisons. The tendency for the sulcus on S4 to be opposed by a strong re-entrant on S2 gives devised by Landing et al., 1980, for Sunnaginia). Sclerites are asymmetrical, and occur as left or the sclerites a 'waisted' appearance. This distin guishing character suggests that the Australian right variants. Asymmetry is most obvious in material may be' a new species, but insufficient terms of SI, which is typically much Steeper than either S2 or S3. Ll is generally relatively short, material is available to assess variation. Material from Nova Scotia and Comley, England, L2 elongate, although in some sc1erites they are described as S. angulata' (Brasier, t986b), is more or less subequal. L3 is' distinguished by a similar with the concave S2 and S4 and a rostrate prominent rostrum along its length. The apertural L1, but the area bearingL3 and L4 is typically margins defined by SI and S2+S3 are recurved; more inflated than in' the Australian specimens. the former is variable, whereas the latter margin is almost always strongly indented, especially S. neoimbricata may also possess strongly con r cave S2 and S4 (Brasie , t986b, fig. 2t), andJike about the rostral termination. The smooth inte ' L3 is typically obtuse the Australian specimeris rior (Fig. 86C,E, K,N,O) is defined by the final ' to rounded. septum of an adapical series. Exterior ornamentation consists of more or less r Family uncertain [SCM, SB] " p ominent growth lamellae that become nodular or pustulose, especially alongL2. Occasionally Kulparina Conway Morris & Bengtson, gen. reticulate patches occur on the external surface novo '(Fig. 88D). , r
"
'
Etymology. For the Kulpara Lst. Type and only species. Ku iparina rostrata Spa
novo
Distribution. Lower ,Cambrian of South Austra lia (Yorke Peninsula).
Comparisons. K. rostrata h a s s o me close similarities to other tommotiids, especially Sun naginia and Eccentrotheca. It resembles the' former genus 'in that �. imbricata tends, to a triangular outline (Missarzhevsky in Rozanbv et al., 1969, pl.8, figs 1-3; Matthews & Missar zhevsky, 1975, pl.1, figs 10,11), although the
EARLY CAMBRIAN FOSSILS, S. AUST.
137
Fig. 86. Kuiparina rostrata Conway Morris & Bengtson, gen. et sp. novo Horse Gully, Kulpara Lst., 6429RS103. All x60. A, SAMP30685, lateral view. B,C, SAMP30686. B, lateral view. C, interior view. D,E, SAMP30687. D, lateral view. E, interior view. F,G, SAMP30688. F, lateral view. G, interior view. H,I, SAMP30689. H, oblique view. I, lateral view. J,K, SAMP30690. J, lateral view. K, interior view. L, SAMP30691, lateral view. M,N, SAMP30692. M, lateral view. N, interior view. 0, SAMP30693, interior view.
138
STEFAN BENGTSON et ai.
Fig. 87. Kuiparina rostruta Conway Morris & Bengtson, gen. et sp. nov.,Horse Gully, Kulpara Lst., UNELI858. A-C, SAMP30694, x40. A, oblique view. B,C, lateral views. D-F,SAMP30695, x40. D,lateral view. E, oblique view. F, lateral view. G-K, SAMP30696, x60. G, upper view. H-K, lateral views.
Fig. 88. Kuiparina rostrata Con way Morris & Bengtson, gen. et sp. novo Horse Gully, Kulpara Limestone, UNEL1858. A-E, SAMP30697. A, lateral view, x40. B, upper view, x40. C, lateral view, x40. D, exterior surface, note reticulation in lower right-hand corner, x200. E, lateral view, x40. F, holotype, SAMP30698, exterior surface, x60. G-L, SAMP30699. G, interior view, x40. H, lateral view, x40. J, lateral view, x40. J, lateral view, x40. K, exterior surface, x120. L, oblique view, x40. M-Q, SAMP30700. M, lateral view, x40. N, exterior surface, x120. 0, interior view, x40. P, lateral view, x40. Q, lateral view, x40.
EARLY CAMBRIAN FOSSILS, S. AUST.
139
140
STEFAN BENGTSON eta!'
Fig. 89
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 90
141
142
STEFAN BENGTSON et al.
Type species.Paterimitra pyramidalis Laurie" . . 1986. · .
."
. Other species.' Laurie (1986) d'i scussed the likelihood that the triaterial illustrated by Tate (1892, p.185, p1.2, fig.19) as Ambonychia mac roptera and plate type III of Dailyatia ajax (Bis choff,1976, p.13,pl.4, figs 36-40,not plate types I, 11, IV-IX; see also Bengtson, 1977, p. 19-20) should be placed in this genus as P. ?macroptera. Distribution. Lower Cambrian of Australia (Northern Territory arid South Australia). Diagnosis. See Laurie, 1986, p,446. Paterimitra pyramidalis Laurie, 1986 (Fig� . . 9�
. Fig. 91.· Kuiparina rostrata Coriway Morris & Bengtson,gen. et sp. nov. Sketch showing orientation of the sc1erite. S face; L lobe. . =
=
basic quadriradiate pattern persists. The rostrum ofK.rostr.ata is similar to that of S. parva and S. .angulata (Brasier, 1986b), where it is borne on L1 .. However, . attempts to homologize the . rostrate 10be�.9fK rostrata (L3) andSunnaginia , (L1) may .be prematur.e� It! comparison with Ec ·centrotheca, this species may be similar in side view, butdiffers in having a more defined shape, �growt4_lamel1ae,and a rostral lobe. ,
.
.
Family uIlcertain [SCM] , Paterimitra' Laurie,1986
.
-
11892 AmbonychidMiller; Tate, p.185.
?*1976 Dailyatia Bischoff, p.13. [partim.] 1985 . Problematicum A (gen. et sp. nov.);, Laurie & ,'.; - ' Shergold,p.8S.
1986
Paterimitra Laurie, p. 446.
Material and distribution. Laurie's (1986) type material is from the Todd River Dolomite south west of Santa Teresa Mission, near Alice Springs; one figured specimen from the Ajax Lst., UNEL1822, Mt. Scott Ra. Diagnosis. See Laurie, 1986,p.446. Description. The specimen illustrated corre sponds to Laurie's (1986) description� Minor differences, taken as intraspecific variation, are the broader growth lamellae, that in our speci men total c. 10. In Laurie's (1986) specimens of the same size about 20 lamellae are discernible. The reticulation on the lamellae is striking (Fig. 92C,D). Its possible significance with r�gard to epithelia! imprints has been discussed above with reference to Kennardia and Sunnaginia.. This description extends its range into South Australia� Tommotiid suprageneric taxonomy
This topic has been discussed by' Bengtson (1970, 1977, 1986a) and Landing (1984). New information (Laurie' the tommotiids as a natural group, but places in
Fig. 89. Kuiparina rostrata Conway Morris & Bengtson, gen. et sp. nov. Horse Gully,Kulpara Lst.,UNEL1858. A-C, SAMP30701. A,lateral view,.x60. B, interior view, x60. C,anterior view, x60. D-G, SAMP30702. D, . interior view, x40. E, exterior surface, x200. F, lateral view, x40. G, dorsolateral view, x40. H-K,M, SAMP30703. H,lateral view,x40. I, dorsolateral view,x40. J, lateral view,x40. K,lateral view,x40. M,exterior surface,. Fig. 90. Kuiparina rostrata Conway Morris & Bengtson, gen. et sp. nov., SAMP30704. Horse Gully,Kulpara Lst,UNEL1858. All x40 except F (x120). A,dorsolateral view. B, lateral view. C,lateral view. D, dorsolateral view. E, upper.yiew. F, exteri()�r surface. G,lateral view. H� upper-lateral view.
Fig. 92. Patei:imitra pyramidalis Laurie,1986,SAMP30705. Mt. Scott Ra., Ajax Lst., UNEL1822. A,B,x90. C,growth lamellae, x400. D, detail of ornamentation, x600� E, x50. F, growth lamellae,x200.
EARLY CAMBRIAN FOSSILS, S. AUST.
143
144
STEFAN BENGTSON
et
al.
some doubt utility of the various families (see also Conway Morris & Chen, 1990b). In essence, the problem emerging is how recognition of mor phological intermediates might 1ink ostensibly separate families. Thus, Lapworthella may ap proach the mitral sc1erites of Camenella. Dail yatia, formerly assigned to the Tommotiidae, is now provisionally placed with Kennardia by Laurie (1986) because both haveJat least three distinct sclerite variants in comparison with the two (mitral and sellate) of Tommotiidae. Sunnaginia and Kuiparina approach each other quite closely. A transformation from a basic triangular to quadriradiate outline (or vice versa)
seems easy to envisage, and could· be one ex ample of a series of minor steps between the 'plastic' form of Eccentrotheca to ultimately the highly organized sc1erites of Camenella and Dailyatia. Intermediate forms could have arisen by minor shifts in patterns of secretory growth. Continuing documentation of tommotiid sc1eri tomes, including an assessment .of morphologi cal variability, must lead to extensive revision of familial taxonomy. It is expected, moreover, that new light may be thrown on these questions by ultrastructural analysis and possibly other fea tures; e.g., trace element chemistry.
EARLY CAMBRIAN FOSSILS, S. AUST.
145
Stoibostrombus Conway MO'rris & Bengtson, gen. nO'v.
ORNAMENTED CONES [SCM, SB]
. Etymology. Greek stoibe,. cushion, pad, and strombos, cone; aliuding to the nature of the fossils as pulvinate cones. Hollow cones and cap-shaped objects bearing Type and only species. Stoibostrombus cren external pustulose ornamentation in (ll roughly ulatus sp. nov. concentric arrangement are known from the Lower Cambrian of China (Luo et aI., 1982, Diagnosis. Broadly flaring hollow cones, typi 1984; He & Yang, 1982), Siberia (Abaimova, cally recurved. Apical tip never preserved, butin 1976), Mongolia (Voronin et al., 1982), France more elongate specimens apical zone more O'r . (Kerber, 1988), and Iran (B. Hamdl, pers. less smooth. Abapically abrupt transition intO' comm.). Stoibostrombus crenulatus gen. et sp. ornamented regiO'n with pulvinate texture, con nov. was first illustrated by Laurie & Shergold sisting of pustulose no�e� or tran�verse ri?&es, . (1985, fig.7P, X) from the Re� ,Heart I?olomite, with well- developed 10ngItudmal fIssures gIvmg Hay River (southern Georgma Basm), who crenulate appearance. Internal surface smoO'th O'r . referred it to ?Ramenta sp. ThIs genus was with subdued pattern reflecting external or originally described by Jiang (in Luo et al., 1982) namentation. Thin wall of phO'sphatic aciculae on the basis of scaly cap-shaped shells from the radiating O'utwards. Cones possibly dispersed Meishucunian of Yunnan. Qian & Bengtson scleritome. (i989) reviewed the Yunnan forms and con cluded that Ramenta, Cassidina Jiang in Luo et Stoibostrombus crenulatus Conway Morris al., 1982, non Milne-Edwards, 1839, and possib & Bengtson; sp. nov. (Figs 93-91) ly Lepidites Zhong [Chen], 1977 [nomen dubium. et nudum] are synonyms of Canopoconus Jiang ?Ramenta sp. Laurie & Shergold, fig. 7P,X. 1985 in Luo et ai., 1982. Canopoconus has well developed scaly ornamentation resembling that Etymology. For the crenulated 'pads' that form i n Stoibostrombus crenulatus. Nevertheless, the external ornamentatiO'n. there "are obvious differences in scale morphol- . ogy and struc!ure (cf. Qian & B�ngtson, �9�9, Material. Holotype SAMP30709 (Fig. 93I-M) figs 56-58 WIth S. crenulatus fIgured heretn), from UNEL1856; 19 figured paratypes and c. 40 and the shell of Canopoconus is cap-shaped with other specimens. rounded apex, rather than conical with pointed apex. Thus Laurie & Shergold's (1985) tentative Distribution. Curramulka (UNEL1845, 1846, suggestion of a relationship between the 1763b' 1847) and Horse Gully (UNEL1854, Australian form and Ramenta [=Canopoconus] 1856) Parara Lst.; Mt Scott Ra., Ajax Lst. cannot now be supported. However, as noted (UNEL1867, 1872-1874); Hay River Northern " below, other rare Australian material may be Territory, Red Heart D olomite (Laune & Sher comparable to the plexus represen�ed by t� e gold, 1985). Chinese taxa. Maikhanella Zhegallo m Voronm et al., 1982, which is often quoted in these dis Diagnosis. As forthe genus. cussions, cannot be evaluated doe to the inade quate O'riginal description, although Kerber Description. Conical ?sc1erites always lack the (1988) accurately described a possibly con apex (Figs 93A,B,F,I, 94A-D,J, 96A,B,�,F,I), generic form frO'm France. , but the uninterrupted taper suggests a sImple terminatiO'n. The basal margin also usually ap pears incomplete, but was O'riginally probably simple, if somewhat irregular. Class and order uncertain The variably recurved cO'nes have a more or less circular cross section and usually show a Family STOIBOSTROMBIDAE Conway Mor rapid increase in diameter, giving a brevicone ris & BengtsO'n, fame novo (Figs 93A, 94A,J) with an apical ang�e of C. 50°. In a few specimens the rate of expanSIOn leads to Diagnosis. Conical ?sclerites, more or less a cap-shaped sclerite (Fig. 93E). In typical radially symmetrical, with pulvinate external brevicones size variation is limited, (c. 0.25surface. Original mineralogy probably phos 0.5mm in length and width). Ajax Lst. specimens phatic. (UNEL1872-1874), however, are typically elon.
146
STEFANBENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
147
(-
gate, with a modest rate of expansion proximally internal . structure, revealed by polished and (apical angle c. 15°), succeeded abapically by-a etched longitudinal sections; is composed of pronounced flaring (Figs 93F,96A,B,D,G). De bundles of acicular apatite radiating outwards spite a larger size, in excess of Imm, and some (Figs 94L, 95F). These bundles apparently do not what different shape, the ornamentation of Aj ax correspond exactly with-the external ornam�nta Lst. specimens is similar to specimens from other tion. horizons. All are regarded as variants within a Stoibostrombus cf. creDulatus sp. novo (Fig. single species. . External ornamentation varies along the 9� length of the cone. Adapically the surface is smooth, and in brevicones this zone is restricted Materlal. SAMP30727 from the 'Ajax �st. at ' (Figs 94A-C, 95B). In elongate specimens it is UNELI874, Mt Scott Ra. more extensive (Figs 94F, 96D,F, 97A,D,G-I). A narrow transitional zone, separating the Description. From a s ample yielding c on smooth from the ornamented region, bears low spicuously elongate specimens of S. crenulatus ridges with denticulate margm� of varying is a conical fossil with significant differences in ornamentation. A smooth apical area is suc strength (Figs 96H,K, 97E,J). Abapical to .this zone, ornamentation is of a prominent cushioned ceeded by a pustulose zone with prominent nodes in a crudely concentric arrangement (Fig. or pulvinate texture (Figs 93D,G,H,L,M, 941), 98F). Each node forms a broad cone, truncated invariably extending to the basal margin of the cone. Although basal irregularities suggest that distally by a shallow concave depression locally the margin is incomplete, there is no (Fig.98C,E). The node surface is generally . evidence that a buttress ever flanged the aperture. smooth, although proximally furrows may scal lop the basal margin. Located between the nodes The ornamentation often is as transverse ridges (c. O.Olmm high), somewhat irregular (Figs 93G, are irregularly arranged transverse ridges with furrows of varying strength that bear a striking 94C, 95J, 96D,G,J). Elsewhere individual pus tules may approach a quincuncial disposition resemblance to the ornamented zone in S. (Figs 93A,E, 94C). Neady all ridges and pustules crenulatus. For this reason, - as well as overall similarity in shape, this unique specimen is. ten show a subdivision by narrow, vertical furrows, whose pevelopment is widely variable. Furrows tatively retained within the species. restricted to either upper (Fig. 93K-M) or lower (Figs 93G, 95C, 97F) side give a characteristic - Affinities ofS TOIB os TROMB us crenulate appearance. Alternatively, these fur rows may extend acrqss the entire width of ridge No closely' related form is evident �mong the or pustule. In one specimen the. ornamentation is pleth�ra of scaly conical or ca:p-shaped·T�wer. Cambrian fossils (Kerber, 1988;--Qian & Bengt� interrupted by a circular. welt (c. O.06mm son, 1989). Dimorphoconus gtanulatus from the diameter) which bears subdued crenulations Sheinton Shales (Tremadoc) of Shropshire (Fig. 96E). Its origin is speculative, but it could (Donovan & -Paul, 1985) is known from the be a response to parasitic infestation or incor external mould of a unique partially articulated poration of a foreign body. Adjacent to this welt two narrow, longitudinal furrows can be traced . specimen; it has a central array of conical spi!les flanked on either side by a dorsolateral row of (Fig. 96F). Perhaps they represent damage to the secretory epithelium, but their adapical origin elongate spines. Donovan & Paul (1985) argued suggests that they may be unrelated to the welt that absence of crushing indicates originally itself. 'solid spines. However, even hollow, calcareous The interior - may be smooth or coarsely spines probably would have resisted early com paction. In' common with S. crenulatus, the granular, possibly as a result of epitaxial over spines of D. granulatus may have been hollow, growths. In former cases, a faint quincuncial pattern may be a reflection of the external or but were calcareous rather than phosphatic, and significantly larger. Their granular ornamerita namentation, and in projecting steinkerns the abapical region bears a similarly impressed pattion� at least on the elongate spines, had a circular arrangement, perhaps reflecting basal accretion. - tern (Fig. 96A-C,I). The wall (Fig. 94K) is thin (c� 15-20f.Lm). Its Re-examination_(SCM) indicates that ornamen-
,
_
Fig. 93. Stoibostrombus crenulatus Conway Morris & Bengtson, gen. et-sp. nov. Curramulka, Parara. Lst., , UNEL1846 (A- D), UNEL1847 (E),UNEL1847 (F-H); Horse Gully,Parara Lst., UNEL1856 (I-M); Mt Scott Ra., Ajax Lst., UNEL1872 (F-H). A-D, SAMP30706. A, x120. B, x120. C, x200. D; ornamentation, xlOOO. E, SAMP30707, x120: F-:-H, SAMP30708. F, lateral view� x90. G,H, ornamenta�ion,>;(200. i...:.M, holotype, SAMP30709. I, x90. J, ornamentation, x200. K, ornamentation, xl000. L, ornamentation, xl000. M, ornamen. / tation, x600.
148
STEFAN BENGTSON et at.
EARLY CAMBRIAN FOSSILS, S. AUST.
149
Fig. 95 Stoibostrombus crenulatus Conway Morrison & Bengston, gen. et sp. novo Horse Gully,Parara Lst., (A-C) ; Mt.Scott Ra., A jax Lst., UNEL 1867 (D-G). A- C,SAMP 30716. A,xI20.B, apical region, x200.C, ornamentation , x 400. D-G, SAMP30717. D,xI20. E,xI20. F, inner wall in apical region showing possible shell utrastructure , x 1000.G, ornamentation, x600.
Fig. 94. Stoibostrombus crenulatus Conway Morris & Bengtson, gen. et sp. novo Curramulka, Parara Lst., UNEL1846 (A,C-L), UNEL1763b (B). A, SAMP30710, x200. B, SA MP30711, x120. C, SA MP30712, x200. D-G, SA MP30713 . D, x120. E, x120. F, x120. G, proximal ornamentation, x400. H,T, SAMP30714. H, x120. I, distal ornamentation, x400. J-L, SA MP30715. J, x120. K, longitudinal section (polished), x200. L, detail of K, x1500.
150
STEFAN BENGTSON et al.
Fig. 96. Stoibostrombus crenulatus Con way Morris & Bengtson, gen. et sp. novo Mt. Scott Ra., Ajax Lst., UNEL1873. A, SAMP30718, x40. B,C,I, SAMP30719. B, x60. C, apical region showing internal ornamentation impressed on steinkern, x120. I, x60. D, SAMP30720, x120. E,F, SAMP30721. E, pustule-like structure near apertural margin, x300. F, x 100. G,H,J,K, SAMP30722. G, x120. H, apical region, x400. J, ornamentation adjacent to apertural margin, x300. K, ornamentation towards apical region, x400.
tation of D. granulatus consisted of closely spaced discrete spines, different from the arran gement of the Australian form. Even if a phylogenetic relationship is ultimately un tenable, it seems possible that the cones of S. crenulatus represent sclerites tha t ha d a broadly c o m p a r a b l e a r range m e n t to those of D.
granulatus. Comparisons may also be made with the utahphosphids, in which the cone-shaped structures are built up of button-shaped apatite sclerites, more or less densely set in a matrix of finely granular apatite and sometimes fused into polygonal platelets ( Muller & Miller, 1976; Bengt son,1977; Rep e t ski,1981; Wrona,
EARLY CAMBRIAN FOSSILS, S. AUST.
151
Fig. 97. Stoibostrombus crenulatus Conway Morris & Bengtson, gen. et sp. novo Mt. Scott Ra., Ajax Lst., UNEL1874. A-C, SAMP30723. A, x120. B, internal ornamentation on stein kern surface, x200. C, x120. D-G, SAMP30724. D, x120. E, ornamentation, x200. F, ornamentation, x800. G, x120. H, SAMP30725, x120. I,J, SAMP30726. I, x60. J, apertural region, x120.
152
STEFANBENGTSON eta!'
Fig. 98. Stoibostrombus cf. crenulatus Conway Morris & Bengtson, gen. et sp. novo SAMP30727. Mt. Scott Ra., Ajax Lst., UNELI874. A,B, x 120. C, ornamentation, x600. D, transition zone between apical region and ornamented zone, x200. E, ornamentation, x600. F, ornamentation, x200. 1982,1987). In particular the fine structure of S. c f . crenulatus (Fig.98) suggests such com parisons, but further microstructural investiga tions are needed. Biology. Wall structure in S. crenulatus suggests an apertural secretory zone. The interior of the cone may have been lined, if not filled, with soft tissue, but it played no secretory role because no growth laminae interior to the main wall are evident. With body organization suggested above, S. crenulatus perhaps was a member of the vagrant epifauna, creeping or walking across the sub strate beneath a battery of defensive sclerites.
The broadly flaring nature of the cones from most samples suggests that they coated the sur face effectively during size increase, without need for extensive interpolation of new sclerites. In the Ajax Lst. specimens, however, differences in cone shape hint at a somewhat different mode of growth. Ornamented Cone Form A (Fig. 99) [SCM] Material.SAMP30728 from the Parara Lst. at UNEL1854 in Horse Gully. Description. This unique breviconic specimen has a recurved umbonal region and almost cir-
EARLY CAMBRIAN FOSSILS, S. AUST.
153
Fig. 99. Ornamented cone, Form A, SAMP30728. Horse Gully, Parara Lst., UNEL1854. A-D, x120. E, surface ribbing, x400. F, umbonal area, x400.
154
STEFAN BENGTSON et al.
Fig. 100. Ornamented cones. A,B, Form C, SAMP30729, Mt. Scot! Ra., Ajax Lst., UNEL187 4. A, x120.
8,
x140 . C-E, Form B, SAMP30730, Horse Gully, Parara Lst., 6429RS10 8 . C,D, x120. E, surfa ce ornamentation, x400.
EARLY CAMBRIAN FOSSILS, S. AUST.
155·
cular outline (Fig. 99A-D). The incompletely,> ORNAMENTED TUBES [SCM, SB] preserved margin appears to have been' smooth, . . except where it is deflected beneath the u�bo as Elongate tubes ornamented with either �pines or a shallow fold. An ex.ter�al orna�entatIon .of scales include: Mongolitubulus squamifer from closely space concentnc ndges (FIg. 99E) d�es. the Botomian of Mongolia has bluntly ter out apically, so that the umbo. is s�ooth (FIg. minated scales (Missarzhevsky, 1977). Com99F). Although now phosphatIc, thIS could be parable material has been described from the secondary replacement of a c�1carous shell. Atdabanian (Rhombocorniculum cancellatum This fossil resembles a vanety of ornal1!ente.d . Zone, Adyshevitheca Subzone) of Maly Karatau cone taxa, although even ge�enc companson IS and-�Talassky Alatau, Kazakhstan. (M I. � . not securely ba�ed. The ChInese Canopoconus sarzhevskY,,&Mambetov, 1981; note . speCIfIc and Purella (QIan& Bengtson,l989) have the name misspelt squamites on p. 79, whlle refer same general form, with a shallow umbo�al reence on p. 29 of 'M9ngolotublus [sic] lepidosus entrant. Comparisons, may be drawn WIth C: sp. nov.' is evidently a nomen nudum), from the squamosus from the Yangtze Gorge, HubeI Middle Cambriail Amga Stage of the same (Chen& Xiong in Xing et a!., 1984b, p' 162, p1.4, re gion (Meshko va, 19'85), and from.t he . fig. 10) andP. antiqua f�om.the Nef!1akIt-Daldyn Botomian of North Greenland (Peel& Blaker, horizon of no�hern SIbena (AbaImova, 1976, 1988).' Hinz (1987) descrihed ge?tly curyed . p. 174,.p1.20, fIgS 1,..15), bu,t m most other orna- tubes (Rushtonites spinosus) from th� Lower mented cones the sculpture IS more pustulose and Cambrian of Comley with a bluntly spmose or.;.· divided. Ornamented Cone Form A has at least a namentation that often becorries reticulate. She su perficial resemblance to a numb�r o f noted similarities with Rhom,bocorniculum, and Cambrian monoplacophorans, although ID no ultrastructural comparisons inay confirm such a· . . case does the ribbing appear to be as closely relatio ship. ll spaced. .
.
.
_
.
..
Ornamented Cone Form . B (Fig. 100C-E)
[SCM, SJ3]
. Tubes with a more irregular and pustular or ' ·i1amentation wer e described from the ba�al Tommotian (A. sunnaginicus Zone) as -Tf!m-: motitubulus savitzkyi by Fedorov (1986),'al though he interpreted the pattern as. a steinkern impression. Rozanov (198?, p.8�) sugge�ted that 'a new famil y, Mongohtubuhdae, mIgh�· b�' erected' to house Mongolitubulus a n d Tom� motitubulus (consisten�ly missp�lt To.mmqtotu, bulus);but at present thIS famI..ly name IS a �o�en nudum under ICZN regulatIons. similar material from China,- however, has been referred to the archaeocyathid Tumuliolynthus. T. macrospinosus from the Meishucunian' (Yuhucun Formation, Zhongyicun. M�mber) of Yunnan (Jiang in Luo et al., 1982; X:1ng ·e� al., 1984b) consists of e�ongate cones bear!.ng spInes. Very similar matenal from the NanJIang ar�a, Sichuan, was described by Yang& �e (1984; see also Yang, et al., 1983, whe�e the .taxon appears as a nomen nudum).· Specimens of T. "!acro- . . spinosus from the late Lower Cambnan· of Hainan Island. (Jiang& Huang, 1986) appear to be different, and referable neither to T..macro..., spinosus nor the archaeocy athids. Other material from this locality that Jiang & Huang (198?) identified as T. tubexternus is also� of uncertaIn systematic position, but c;tpparently:distinct from the ornamented tubes. . .
Material. SAMP30730 from the Parara Lst. at
6429RS108 in Horse Gully ..
D·escription. A gently convex plate with a tear drop outline and well defined margi�s. Orna mentation of concentric and somewhat Irregular, closely spaced ridges (Fig. 100E) dies out towards the edges: A similarity, ·possibly super ficial, may exist with the enigmatic Cambrocas . sis verrucatus (Missarzhevsky, 1977, p1.2, fIg. 7, text-fig. 1.19) from the Atdabanian of the Bateny Hills (near Abakan, Khakasskaya AO), and �os sibly also the ·Siberian Platform and MongolIa. Ornamented Cone Form C (Fig. 100A,B)
[SCM]
Material. SAMP30729 from the Ajax Lst. at UNEL1874, Mt Scott Ra. Description. This shield-like �ossil is gently C�)fl cavo-convex, with the extenor surface beanng subdued irregular wrinkles that die out towards the presumed posterior. The incom�let�ly preserved margin was probably smooth I.n lIfe. This specimen does not appear to be dlfe�tly comparable to any of the taxa of ornamented cones mentioned above.
_
Squamate fragments and tubes. described as Anatolepis are known from a v.a�Iety of UpJ?er Cambrian and Lower .Ordovlclan IqcahtIes (Bockelie& Fortey, 1976; Bockelie, Bruton&
156
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST :
157
Fig. 102. Ornamented tube, Form B. SAMP30733. Horse Gully, Parara Lst., UNEL1854. A, x90. B, x90. C, x400. D, x600. E, x600. F, x600. G, x900. Fig. 101. Ornamented tube, Form A, Kulpara, Parara Lst., 6529RSl 05. A-C, SAMP30731. A, entire specimen, x60. B, detail of apex, x400. C, detail of apertural region, x400. D,H, SAMP30732. D, entire specimen; x60. H, detail of apertural region, x400. E-G, SAMP30984. E, entire specimen, x120. F, detail of apertural region, x400. G, detail of tube wall and underlying steinkern, x900.
,,::.
STEFAN BENGTSON
158
et
al.
sqami/er" fio� t h e u p p er A t daba n i a n o f Fortey, 1977; Peel; 1979), but there, is debate whether these fossils represent arthropods or ver 'Kazakhstan (Missarzhevsky & Mambetov, tebrates. Such similarities that exist with the 1981); a suite that differs from the type assem� Lower Cambrian forms mentioned �b. blage on 'account of its more rounded scales. superficial, and ultrastructural studies are re-' Some similarities may exist 'also with Rushto.., nites spinosus' ftom the Lower Cambrian' of quired. Comley (Hinz, 1987), but Omamented Tube, Ornamented Tube Form A (Fig 101) . Form B shows less curVature, differences in tubercle arrangement; and possibly original Material. SAMP30731,.30732, 30984 and c. 30 mineralogy.' other specimens from the Parara Lst. at" Ornamerited T"be Form C (Fig. 103) UNEL1860B, 6529RSI03-106, 108, 111, ?110 on the Kulpara Road· section. MateriaL SAMP30734,' 30735 from the Ajax De�cription. ,Thes� elongate structures (Fig. Lst. at UNEL1871 and �877, Mt Scott Ra. 101A,D,E), which may,exceed 1.5 mm in length, consist of a thin phosphatic wall often, enclosing Description. This material resembles closely a' steinl<em (Fig� 101D,G). Th.e phosphate may ,Form 'B, differing in that the surface scales are l?e pri,mary ca]careous skeleton. The apex is bluntly conical low ridges that radiate across the intervening (Fig.l01B)� and at the opposite end the tubemay areas (Fig. 103G,H). Tube dimensions are similar to those of Form B; the unusual width flare (Fig. 101C), but the intervening section show s minimal i n c r e a se in , d i ameter ( c . (0.3mm) o f one specimen (Fig. 103B) is evi O.15mm). The surface bears many short; spinose' dently due to crushing which is reflected also in ,p�ojections. Close to the apex they are dens�ly a longitudinal fold. packed and adapically inclined (Fig. 101B), but along th_e' remainder of the tub,e they (c. 0.02mm . SMOOTH CAPS [SCM] , high) scatter. cates the spines, they are assumed to have been Mobergella (and the closely related Discinella); " hollow.· with a low cap-like. shell, eC, internal radiating muscle scars, has been dis� 'The�;e fossils 'are enigtnatic, and no similar material appears to have been described from cussed by Bengtson (1968). Other accounts have . elsewhere., " demonstrated its wide geographical distribution .
'
.:"
.
,i
-
.
..
.
(Meshkova, 1969; Rozanov et al., 1969; Beng-, Ornamented Tube Form B (Fig. 102) tson, 1970; Meshkova in Repina et al., 1974; ,Lendzion, 1972a,b; Bulygo et-al., 1981; Sokolov Material. SAMP30733 from the Parara Lst. at & Zhuravleva" 1983) and stratigraphical range UNEL1854 in Horse Gully. into the upper Atdabanian (Rhombocorniculum cancellatum Zone, see Missarzhevsky & Mam Description. These tubes consist of a thin phosbetov,1981). Yunnan specimens referred by He phatic wall and steinkern filling (Fig. 102A,B, & Yang (1982) to the monoplacophorans as F). The 2-layered wall (Fig. 102A) suggests that Palaeacmaea bella were tentatively referred to phosphate was deposited on either side of an Mobergella by Qian & Bengtson (1989); doubt originally calcareous tub�. Neither end of the remaining because of the absence of the diagnos- ' tube is preserved. The ornamentation consists of -tic muscle scars. blunt scales (Fig. 102C�G), the spacing and ar' Remaining Chinese mobergellids app'ear rangement of which is somewhat 'irregular. highly questionable. Material from Sichuan Close resemblances exjst with material from referred to as Mobergella? sp.(Yin et aI., 1980) the upper Lower Cambrian of Hainan Island, that . �may be compared better wi�h the admittedly Jiang & Huang (1986, p1.2, fig.ll,11a) referred poorly known Emarginoconus (Yu, 1979; note to the archaeocyathids as Tumuliolynthus mac... that Diandongoconus He & Yang, 1982, i� a rospinosus, an assignment not accepted here;, ' junior objective synonym) 'arid some specimens Similarities exist also· with Mongolitubulus referred to '-:4egides'·plac.us (Jiang in Luo et al., .
.......
-
Fig. ]03. Ornarnented tube, Form C. Mt. Scott Ra., Aj ax Lst.� UNEL1871'(A-D), UNEJ.J877(E-H)� A-D, SAMP30734. A, ornamentation, x 120. B, x90; C, ornamentation, x600. D, oblique view 6fornamentation, x400. E-H, SAMP30735. E, x120. F, tube wall and underlying steinkern, x200. G, ornamentation, x600. H, ornamentation, x400.
EARLY CAMBRIAN FOSSILS, S. AUST.
159
160
STEFAN BENGTSON
et
al.
1982, p1.20, figs 12, 14; nom. corr. pro places, Qian & Bengtson,1989; note that these parat�pes appear,-to differ mar�edly from the holotype; compare also with A. cf. placus in Jiang &'. Huang, 1986). Material identified as Mobergel la? sp. from the Meishucunian of Yunnan by Jiang (in Luo et al., 1982) appears to represent orthothecid opercula, and this may apply to fos sils from the same area that Jiang (1980a; see also Luo et ai., 1980) placed in ?Mobegella [sic]. Inclusion of this taxon in stratigraphic range charts of the Yurinan Meishucunian (Xing et ai., 1984a,b;-Xing & Luo, 1984) appear to be without foundation. Fossils from Guizhou that Qian & Yin (1984a; see. also Wang et al., 1984b) iden tified as Mobergella ·?guizhouensis (variously misspelt Mobegella, Moberella and Morbegella) possess radiating ridges, but seem. distinct from. Mobergella. Finally, Gao et al. (1982, p. 525) refer to Mobergella sp. from the Aksu-Wushi region' of Xinjiang, but this identification is dubious in the absence of illustrations. Other material from Ningqia'ng, Shaanxi, has been referred to as Paramobergella ningqianensis (Zhong [Chen], 1977), but this taxon is- a nomen nudum, and notwithstanding its generic name Chen (1982) subsequently, in comparing it to Olivooides and Archaeooides, erected the new genus Protosphaerites.
. wrinkled- texture (Fig.105D). ,Similarities with Mobergella ate probably superficial, but no other . affinities are evident. .
.
.
.
Smooth Cap Form A (Fig. 104) Material. SAMP30736 from the Parara Lst. at
UNEL1848, Curramulka.
Description. This specimen (c. 0.37mm diame
ter) consists of a centrally placed cone, occupy ing about a third of the diameter, flanked by a broad brim beadng concentric ridges that may represent growth -lines. A gentle fold extending from the cone across the brim defines slight bilateral symmetry (Fig. 104A,C), and the mar gin in this region is deflected slightly upwards. The interior (not illustrated) is smooth, ·without . obvious muscle scars. Similarities with Mober gella seem to be superficial, and this fossil may represent an operc�lum, possibly of a hyolith.
Smooth �ap Form B (Fig. .105)
SMOOTH CONES [SCM, SB] Steeply. conical, thin walled fossils from the Tommotian have been referred to Fomitchella (F. infundibuliformis Missarzhevsky in Rozanov et al., 1969; F. acinaformis Missarzhevsky, 1977), whose similarity to conodonts is belied by a distinctive ultrastructure (Bengtson, 1983). Few undoub.ted records of Fomitchella exist from beyond the Siberian platform, e.g. from the Avalon Zone (Landing & Brett, 1982; Bengtson & Fletcher, 1983; Landing, 1988), and the majority of identific ations appear t o be erroneous. Thus, reference to F. cf. infundibuli [ormis (Jiang in Luo et al., 19 82), F. acinaci [ormis (Xing et al., 1984b), F. inchoata (Yang & He, 1984; note that reference to this taxon by Yang et al., 1983, is 'as a nomen nudum), F. rugosa (Jiang in Luo et al., 1982); F. yankonensis (Yuan & Zhang, 1983), Fomitchella sp. (Yin et al., 1980; Jiang in Luo et al., 1984), and Para[or michella [sic] orientalis (Qian & Zhang, 1983) cannot be supported (Bengtson, 1983). Alterna tive identifications are usually impossible, and some may be regarded better as nomina dubia. F. inchoata may be trilobite pleural tips. A distinctive conical fossil, only superficially comparable to Fomitchella, is described here, and possibly similar material from the Siberian Platform receives brief comment Class, order, family uncertain
Archaeopetasus Conway Morris & Bengtson,
gen. novo
Etymology. Greek archaios, ancient, and peta sos, broad-brimmed hat, thus old hat. Type and only speCies. Archaeopetasus undul atus sp. nov. Distribution. Lower Cambrian, South Australia.
·
Material. SAMP30737 from the Parara Lst. at UNEL1856, Horse Gully.
(c.
0.9 mm diameter, 0.23mm high) is strongly conca vo-convex, with an ,eccentrically located apex (Fig. 105B,C). The outer surface is smooth (Fig. 105A), whereas the inner one is traversed by an anastomosing series of grooves imparting a
Description. The only known' specimen
Diagnosis. Centrally located cone, of widely
varying height, straight to recurved, surrounded by broadly flaring brim, sometimes with mar ginal folds or crenulations. Composition probab"'ly originally calcareous.
Archaeopetasus excavatus Conway Morris &
Bengtson, sp. nov. (Figs 106, 107)
Etymology. On account of its hollow interior.
EARLY C AMBRIAN FOSSILS, S. AUST.
161
Fig. 104. Smooth cap, Form A. S A MP30736. Curramulka, Parara Lst., U NEL1848. A-D,F, x200. E, detail of . surface, x400. .
162
STEFAN BENGTSON et al.
Fig. 105. Smooth cap, Form B. SAMP30737. Horse Gully, Parara Lst., UNEL1856. A, lateral view, x90. B, oblique view of interior, x90. C, interior, x90. D, interior wall showing irregular grooves, x200. Material. Holotype SAMP3 0738 (Fig. 106 A-C) from UNEL1760; five figured paratypes and c. 200 addit i onal s pecimens. Distribution. H o r s e Gully ( U N E L 1854, 6429RSI07-109) and Kulpara (UNEL1760,
1860B,C, 6529RSI05, ?6529RSllO and 6529RS113 ), Parara Lst; Mt. Scott Ra., (UNEL1874), Ajax Lst. Diagnosis. As for the genus.
Fig. 106. Archaeopetasus excavatus Conway Morris & Bengtson, gen. et sp. novo Kulpara, Parara Lst., UNEL1760. A-C, holotype, SAMP30738. A, x90. B, surface sculpture, x200. C, interior, x90. D, SAMP30739, x90. E, SAMP30740, x90.
EARLY CAMBRIAN FOSSILS, S. AUST.
163
164
STEFAN BENGTSON et al.
Description. These enigmatic 'fossils are only known at Kulpara, where they are abundant. PreserVed in phosphate, they reveal iQ polished sections a granular texture' without preserved ultrastructure(Fig. 107E,F), s-uggesting diage netic replacement of an originally calcareous skeleton.' The basic shape of a thin-walled flaring cone (Figs 106A,D,E, 107A,D) shows considerable variation in height of the central apex, which although usually straight, is sometimes recurved. The brim-like margin typically shows low amplitude folds(Figs'106A,E, 107A,D), which may develop into more steeply expressed crenulations(Fig. 106D).-The internal surface is smooth(Fig. 106C), but the outer side may bear scattered granules(Fig. 106B). ,
siniUar to hrachiopods. Valve anatomy diff�rs from any known brachiopod, but if they shared a common ancestor with the lophophorates, they may have possessed comparable soft-parts,· in cluding a tentacular lophophore. Both these animals probably had a primary calcareous shell. They lacked an articulation mechanism com parable to the Articulata, but in Apistoconcha gen. nov. a median set of teeth-on one valve articulated with an opposite lateral pair. In con trast, the arrangement in true articulates consists of paired teeth and sockets on opposing valves. Aroonia gen. nov. had a median structure, pos sibly connected to an external ligament; an arran gement unknown in acknowledged brachiopods. Class, Order uncertain
Family TIANZHUSHANELLIDAE Conway. Comparisons. Similarities with Fomitchella are superficialr, but other affinities remain' prob Morris, nov. [SCM] lematic. Abraded cones with missing apices from Diagnosis. Bivalved organism, each valve bear the Tommothin of the Siberian Platform weie ing prominent pair of recessed cavities near illustrated as possible opercula of the tubicolous posterior. Coleolella billingsi(Rozanov et al., 1969, pl.7, figs,�,15',16). They appear to be larger than A. 'und.ulatus, but these are minimum estimates(c. Comparisons. Tianzhushanella ovata Liu, 1979, l-LSmmtbecause of incompleteness. An ap-' (type species) was described from the Lower parently similar cone from the Tommotian of Cambrian ,Upper Dengying Formation in West Kharaulakh was interpreted by Meshkova(in Hubei near Yichang(Yangtze Gorges) and unit Repin� et al., 1974, pl.19, fig.l1) as a possible 8, upper member of Dengying Formation, Yuan operculum of Hyolithellus vladimirovae,(comjiaping section, Ningqiang, Shaanxi(Xing & parisons by Chinese workers with zhijinitids are" Yue in Xing et al., 1984b). Jiang(in Luo, et aI., 1982, p.138)noted Tianzhushanella sp. from the discussed above)� ,Although considerably larger (c; 3inm according to magnification given), the Meishucun section(Bed 7, Zhongyicun Mem ber); but provided no illustrations. Liu(1979) undulating brim is comparable to A. undulatus. regarded Tianzhushanella as a brachiopod, a placement regarded as questionable by Xing & BIVALVED ORGANISMS OF Yue(in Xing et al., 1984b). The Chinese material 'POSSIBLE BRACHIOPOD is not well known, but unp.ublished observations 'AFFINITY [SCM.,SB.J, (SCM) justify generic distinction between· . Tianzhushanella and Apistoconcha. Steinkern Two Australian taxa with bivalvedshells possess, structures that Liu(1979, p.S11) referred to as 'small nodules at the ventral oeak'(Liu, 1979, an antero-posterior plane: of bilateral symmetry _
�...
Fig. 107. Archaeopetasus excavatus Conway Morris & Bengtson, gen. et sp. nov.· Kulpata, Parara Lst., ,6529�S105 (A-D), UNEL1860 (E,F). All x90 except E (x200) and F (x2000).. SAMP30742. E,F, SAMP30743, transverse section (polished). , Fig. 108. Apistoconcha siphonalis Conway Morris, gen. et sp. nov., dorsal valves. Horse Gully; Parara 1.st., UNEL1852. All x60 except D and H (x120). A,B; SAMP30744. A, interior view. B, oblique posterior view. C, SAMP30745, interior view. D,E, SAMP30746. .0, teeth and posterior pits. E, anterior view of interio. SAMP30747, steinkern. F, interior. G, anterior view showing umbonal cavjties and anterior cavity. H, SAMP30748, posterior view. ' '
,
-
,
,
.
Fig. 109. Apistoconcha siphonalis Conway Morris, gen. et sp. nov., dorsa�: valves. Horse Gully, Parara Lst,
UNEL1852. A,B, SAMP30749, steinkern. A, posterior view, x60. B, lateral view,of anterior cavity, x200. C, SAMJ'30750, steinkern"'anterior view, x60. D,H ,T; holotype�.SAMP30751, steirikern. D, anterior view, x60. H, uinbonal� cavi�ies, x200. I, x'60. . at anterior X-bOo J, stefnkern and posterior wall (epitaxial overgrowth), x45. K, interior of wall showing growth increments and possible shdl ultrastructure,. x600. F,G,L, SAMP30753. F, exterior view, x120. G, lateral view, x120. L, exterior view, x60.
:
.
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 107
165
166
STEFANBENGTSON etal.
Fig. 108
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 109
167
168
STEFAN BENGTSON etal.
Fig. 110
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 111
169
170
STEFAN BENGTSON etal.
/'
Fig. 112
EARLY CAMBRIAN FOSSILS, S. AUST.
p1.2, fig.8; Xing & Yue in Xing et al., 1984b, p1.26, fig.17) apparently are equivalent (in posi tive relief) ,to the umbonal cavities of Apis toconcha. The former genus tends t&- be more , elongate, somewhat less conve'x, and has m' closely spaced umbonal cavities. Critical points of comparison, such as mode of articulation and possible posterior pits, have not been recognized in Tianzhushanella.
Apistoconcha Conway Morris, gen. nov.
Etymology. Greek apistos, doubtful, and konche, shell; an oblique reference to its possible ' brachiopod affinities. Gender is feminine. Type species. Apistoconcha apheles sp. novo Other species.A. celsa sp. nov.,A. siphonalis sp. novo Distribution. Horse Gully, Curramulka, and Kul para, Parara Lst.; Mt. Scott Ra., Ajax Lst.; Flinders Ra., Oraparinna Shale. Diagnosis. Bivalved organism with dorsal and ventral valves, plane of bilateral symmetry bisecting both valves. Each valve with steep to posterior margin, more gently inclined lateral, and anterior margins. Externally prominent growth lines. Internally each valve has pos.terior plate housing a median recess or recesses, and bearing elongate tooth-like structures either lo cated about the midline in an arcuate bar (in the valve arbitrarily considered dorsal), or located laterally (in the ventral valve). In umbonal area
171
interior of vaIv� houses a prominent pair of cavities, while in the anterior region a 'median ' recess exists.
Comparisons.Apistoconcha and Tianzhushanel;. la are evidently related, but the generally-inferior preservation of Chin'e se material does, not facilitate detailed comparisons b�'yond overall shape and shared possess}on of umbonal pits. "
Preservation. Complex preservation (Fig. 113) is broadly comparable to the several varietier; documented in the co-occurring bivalve mollusc Pojetaia runnegari (Runnegar & Bentley, 1983). However, unlike the latter, valves of Apis toconcha are almost invariably disarticulated. Steinkerns (Figs 108F,G, 109C;D,I) are charac teristic of A. siphonalis sp. novo at UNEL1852. Here the valve interior is partially or entirely filled with phosphatic sediment, usually includ ing skeletal fragments and other debris. The steinkern surface adpressed to the interior of the valve often replicates shell ultrastructure in ex� quisite detail (Fig� 112). Another style ofpreser vation is a thin coat of light brown phosphate (Fig. 111), similar to the epitaxial coating noted in Pojetaia runnegari (Runnegar & Bentley, � 983). When it:covers the outer surface,growth Hnes are still clearly displayed (Fig. 110E,I); while examination of the inner side reveals both growth increments and reinnants of sh"e ll ultrastructure. In specimens where the valve 'is without an interior filling, this coat forrn� 'a uniform layer around the inside of the valve as well (Fig. 116A,B), while when the interior is filled with sediment (steinkern) the epitaxial layer again provides a coating in continuity with that covering the rest of the specimen (Figs
Fig. 110. Apistoconcha siphonalis Conway Morris, gen. et sp. nov., ventral valves and one possibly articulated
specimen (C). Horse Gully, Parara Lst., UNEL1852 (A-D, F-H) and UNEL1762a (E,I). A, SAMP30754, exterior view, x60. B, SAMP30755, shell wall phosphatized and showing possible u1trastructure, x200. C, SAMP30756, (?)articulated specimen with we]] preserved dorsal and possible ventral valve, x120. D, SAMP30757, posterior region with teeth, x90. E,I, SAMP30758. E, exterior view showing outer surface (epitaxial overgrowth) and steinkern of inner surface, x60. I, anterior view, x90. F, SAMP30759, interior view with details largely obscured by epitaxial overgrowth, x60. G,H, SAMP30760. G, lateral view of exterior and ' part of steinkern(posterior end), x60. H, sulcus, x200.
Fig. 111. Apistoconcha siphonalis Conway Morris, gen. et sp. n�y,., ventral valves. Horse Gully, Parara Lst., UNEL1852.AlI x60 except D,E(x200) and F(x600). A,B, SAMP30761. A, interior view. B, lateral view. C-G, SAMP30762. C, posterior view. D, notch in posterior margin. E, posterior pit. F, growth lines on exterior. G, ' anterior view of interior. H,I, SAMP30763. H, exterior view. I, lateral view.�" "
Fig. 112. Apistoconcha siphonalis Coilway Morris, gen. et sp. nov., ventra) valves, Horse GulJy, Parara Lst., UNEL1852. A-C, SAMP30764. A, lateral view of steinkern, x60. B, �hell ultrastructure if.l anterior region,
x400. C, shell ultrastructure in median region, x600. D-H, SAMP30765, steinkern. D, posterior, x120. E, anterior view, x60. F, shell ultrastructure on sulcus, x600. G, shell ultrastructure OIJ. anterior region, x200� H, shell ultrastructure on posterior region, x200. I, SAMP30766, detail of ultrastructure on proximal sulcus, x400. J, SAMP30767, detail of posterior region of steinkern showing shell ultrastructure and'posterkir pits' relief), x200.
172
STEFAN BENGTSON et al.
original shell /"
:--1., .
epitaxial coat
�
loss of CaC03 (? by acid digestion )
epitaxial coat
steinkern
D
original shell phosphatic debris epitaxlal coat phosphatlsed shell
Fig. 113. Style of preservation in Apistoconcha spp. with various diagenetic histories leading from original calcareous shell to final preservation as steinkerns, phosphatized shells, epitaxial coatings or variants thereof.
111G, 118e). This suggests that epitaxial growth is a postmortem feature, fonned in freely agitated conditions, rather than developing after burial. However, even though 'in ,biostratinomic terms the valves behaved as coated grains, epitaxial growth was not necessarily primarily phosphatic. Given the apparent difficulties of primary. precipitation of phosphate in open sea-water of present day oceans (Burnett, 1977; Bentor, 1980), an alternative possibility (if unifor mitarian assumptions concerning Cambrian oceans are valid) is that the present, coat repre sents replacement of an originally calcareous layer (Manheim et al., 1975; Lucas & Pn!vot, 1984; Prevot & Lucas, 1986)., Despite the ultrastructural impressions on the steinkern, little remains of the original cal careous shell. In some specimen� the steinkern is separated from the epitaxial coating' of the outer surface by a prominen,t, savity (Figs 109J, 110E),., once occupied by carbonate. In other specimens the original shell material has been phosphatized
(Fig. 110B). Relics of primary structure oc casionally may be recognizable, ,but in general the replacement by tightly adpressed granules has obliterated any textures.
Valve morphology and orientation. Two distinct types of valve are recognizable in A. siphonalis and A. apheles. In A. celsa, however, paucity of material and indifferent preservation make direct confirmation of such an arrangement impossible. The separate valves could be interpreted as either s�xual dimorphs or even different species. The reason for believing that they derive from the same organism lies in the arrangement of the posterior teeth (see below): the median arcuate ridge of morph a, arbitrarily taken as being dor sal, appears to be adapted to articulate with the lateral teeth of morph b� taken to be ventral. Valves almost invariably disarticulated on death, and only one'small steinkern (Fig. l10C) shows possible association. Here the dorsal valve is
EARLY CAMBRIAN FOSSILS, S. AUST.
173
Fig. 114� Reconstruction of Apistoconcha siphonalis Conway Morris, gen. et sp. nov" showing the ventral valve in interior (A), lateral (C), and exterior (E) views, and the dorsal valve in interior (B) and exterior (D) views.
fairly well preserved, but the opposing ventral valve is more obscure.
Apistoconcha siphonalis Conway Morris, sp. novo (Figs lOB-lIS)
Accepting that morphs a and b were conjoined, a dorsoventral orientation seems more likely be cause the plane of bilateral symmetry bisects each valve, suggesting a posterior hinge and anterior gape. There seems no secure guide as to which valve was ventral. In articulate brach iopods, which may be distantly related to Apis toconcha, the ventral valve bears the laterally situated teeth. Until contrary evidence is avail able it is assumed, therefore, that morph b was ventral and morph a dorsal. In all three species the valves are strongly concavo-convex, with steep posterior face and more gentle anterior and lateral areas. The valves grew incrementally, as may be judged by both the growth lines and relative size differences. Apart from the growth lines, the valve exterior appears smooth, although a radial ornament is sometimes visible. The posterior face may be more or less smooth, or may possess gentle fur rows or ridges that parallel the growth direction.
Etymology. Latin siphonalis for the siphon-like structure. Material. Holotype SAMP30751 (Fig. 109D,H, I) from UNEL1B52; 23 figured paratypes and c. 200 other specimens. Distribution. Ho r s e Gu l l y, Pa r a r a L s t. (UNEL1762A, 1852, 1853, 6429RS110-112). Diagnosis. Ventral valve with a prominent anteromedian spinose sulcus. Description. In broad outline both dorsal and ventral valves have a tear-drop shape. Outer epitaxial overgrowths replicate terrace-like structures that parallel valve margins (Figs 110E,I, 111F). Although not always continuous, these terraces presumably replicate growth lines. Their clarity in the posterior region (Figs 10BH, 111C) is presumably because slower growth
174
STEFANBENGTSON etal.· "
Fig. 11S. Inferred soft parts of Apistoconcha. The longitudinal section is simplified in that the umbonal cavities lie either side of the midline, as do the po-sterior pits of the dorsal valve� The posterior pits are depicted as muscle insertion areas here, but alternative possibilities such as ligament pads are considered in the text. Details of the gut and feeding organs are hypothetical.
rates, in comparison to the lateral and anterior regions, led to their closer packing. Dorsal valves have a smooth anterior margin (Figs 108A,F, l09F,I,J,L) that, in contrast to that of ventraIs, lacks a median projection. Externally the posterior margin is steep, and on either corner a prominent narrow fold extends posteriorly (Figs 10BA-E,H, 109J,L). The basal part of each fold is often infilled with sediment, so that in steinkerns the folds typica11y are represented by prominent prongs (Figs 10BG,F, 109A,C-E,I). Internal morphology of the dorsal valve is complex. Near the posterior margin a pair of relatively discrete tooth-like structures lie on either side of the midline, separated by a median platform with more subdued relief. On the inner (anterior) margin, teeth and platform define a steep scarp that imparts an arcuate appearance to the entire structure (Fig. 10BA,C,E). Each tooth is elongate, and there is a suggestion that some times the teeth were scalloped (Fig. 10BD). Ad jacent lo the posterior ends of the teeth, i.e. about the midline, a pair of prominent recesses are
. '-'
termed the posterior pits. They are relatively subdued when covered by an �pitaxial over growth (Fig. l08D,E), but in steinkerns they form prominent peg-like extensions,- somewhat elongate transversely (Figs 1OBF, 109A,E,I). The region adjacent to teeth and posterior pits forms a broad brim, but anteriorly this narrows into a marginal rim, defining a deep interior cavity that presumably housed most of the soft parts (Fig. 108E). In the interior of the umbonal region another pair of prominent recesses define the umbonal cavities. Best seen in the steinkerns, they form narrow extensions (Figs 108F,G, 109C-E,I), elongated antero-posteriorly, but with a pqsterior slant and rounded termination (Fig. l09H). Their outer side is a direct continua tion with the valve wall, and frequently a track like extension extends from the-se' cavities towards the lateral margins (Figs 10BF,G, 109C). In addition to the umbonal cavities, the interior of the dorsal valve possesses a prominent anterior recess, flanking the midline (Figs 108F,G, l09A,C,D,I). This anterior cavity is a posteriorI y directed pit (Fig. 109B), elongate transversely. The anterior region may also bear a pairof low ridges (known as the anterior folds) that diverge anteriorly and run towards the mar gins. On steinkerns they form shallow grooves (Figs-l0BG, 109C,D,I), while in specimens with epitaxial overgrowth they define low ridges (Fig.. 108B,C). Most developed adjacent to the margin, these folds rapidly become more subdued posteriorly. Extemally ventral valves (Figs 110-112) are dis tinguished by the medial extension .of the anterior margin as a narrow sulcus. This sipho nate structure is a spinose infill in steinkerns (Fig. 112A,E), but in specimens with epitaxial over growth the incremental growth of the anterior sulcus can be traced along much of the anterior (Figs 110A,E,F,I, 111H,I). Occasional interrup tions in sulcus growth are recognizable by a I ip-like extension (Fig. 110H). The remainder of the valve outline is smooth, and unlike the dorsal valve the posterolateral corners are rounded and lack the fold-like extensions (Figs 110A, 111A,H). . Internal morphology of the two valves is similar. However, the lateral elongate teeth of the ventral valve are separated by a wider median platform (Figs 110D,F, 111A,B,G), which houses a posterior pit. Unlike those of the dorsal valve it is, single, straddles the mid-line (Fig. lllA), and forms an elongate depression con taining a deepe-r median area with a rhomboid outline (Fig. 111E). The posterior side of this pit ext�nds as a shallow groove so that the valve margin is notched (Fig. 111D). In steinkerns only the central pit is preserved, as a peg�like projec-
EARLY CAMBRIAN FOSSILS, S. AUST.
tion (Figs 110E, 112D,H) which occasionally is paired (Fig. 112J). The umbonal cavities (Figs 110E, 112A,D, E) are similar to those of the dorsal valve. However, neither an anterior cavity nor anterior ridges are present in the ventral one, although in some specimens the anterolateral margin has a low deflection (Fig. 110G) that may correspond to the anterior ridges on the opposite valve. In steinkerns, i nner she1 l ultrastructure (Fig.112) is often preserved as in some Cambrian molluscs (Runnegar & Bentley, 1983; Runnegar, 1985b). The ultrastructure is uniformly foliated, although the linear trend of this fabric shows considerable variation over the valve. Around the edge of each valve is a fibrous zone (Fig.112A-C,G). The antero-posterior orienta tion of the fibres results in their trending oblique ly to the valve edges. This marginal zone is especially obvious anteriorly (Fig. 112B,G), and along the sulcus of the ventral valve the fibres are parallel to its axis (Fig. 1121) and often have a step-like arrangement (Fig. 112F). Posteriorly, the marginal zone is indistinct, in part because the steinkern edge tends to be incomplete. Away from this marginal zone the fibre trend around the entire valve is more oblique to the valve margins (Fig. 112A,G), except on the posterior face where the fibres sweep towards the umbonal cavities (Fig. 112D,H,J). In the central-anterior region. of the valve, the fibrous zone is only patchy (Fig. 112E). This fibrous structure, which presumably was aragonitic, may have occupied the entire thick ness of the original shel1, if two lines of evidence are accepted. In one specimen (dorsal) the inner surface of an epitaxial overgrowth of the posterior region is visible. In addition to prominent growth lines a fibrous ultrastructure (Fig. 109K), running more or less orthogonally, appears comparable to that of the steinkern sur face. In another specimen (ventral) unusually the entire wall appears phosphatized. If obliquely inclined structures running through the shell are original fabric (Fig. 110B), this suggests a uniform ultrastructure..
Mode of life. Despite only one specimen of a possibly articulated individual (Fig. 110C), the relative proportions of each morph and ar rangement of the articulatory teeth support a bivalved reconstruction. In a suite of 150 specimens from UNEL1852, 35 were unidenti fiable, but of the remainder 59 (51%) were at tributable to morph a ('dorsal') and 56 (49%) to morph b ('ventral ) Even more compelling is the invariable location of the teeth in each morph. However, although the median versus lateral dis position of the teeth in morphs a and b, respec'
.
175
tively, provides a plausible hinge mechanism, in A. siphonalis (although apparently not in the stratigraphically older species; see below) the juxtaposition of the margins of the two valves appears to have been far from exact. Thus the posterior flanges of morph a and anterior sulcus of morph b fail to have matching counterparts. Whether the resultant gaps were covered by soft tissue or even small plates, comparable to the stegidial plates of some brachiopods (Cowen, 1968) that detached after death, is not clear. A. siphonalis was presumably sessile and ben thic. No evidence exists for attachment by struc tures analogous to a pedicle, and the animal probably was free-lying. Shell thickness in the posterior region may have acted as a counter weight as the animal reclined in coarse carbonate substrates. All species of Apistoconcha (and Tianzhu shanella) probably were suspension feeders. The well-known partition of laterally disposed in halent and median exhalent feeding currents in brachiopods invites comparison with these fos sils. No epizoan encrustation has been observed that might act as a guide to points of water flow, but if the analogy is accepted this would suggest that the water entered on the lateral margins and was expelled along the median sulcus. Lateral intake may have been controlled by the slight sulci in at least some ventral valves (Fig. 110G), while the anterior ridges in the dorsal valve (Figs l08C,G, 109C, D) may have acted also to pa:rti tion water currents, especially if these supported a curtain of soft tissue. Expulsion of water along the median sulcus as a fine jet would have helped to avoid mixing and inadvertent recycling. Internal soft parts are largely speCUlative. Co marginal growth lines (Figs 109F, 110E,G) indi cate that the shell grew by accretion, and almost certainly the interior surface was lined by a secretory mantle tissue. The change in direction of shell ultrastructure beyond a well-defined marginal zone (Fig.112A,G) could be analagous to the pallial line of bivalve molluscs. If com parisons with bivalved suspension feeders, such as molluscs and brachiopods, are taken as a guide, m uch of the interior was filled with a ciliated feeding organ, with the rest of the body located in the deep umbonal regions near the posterior (Fig. 115). As in other bivalved organisms there must have been an antagonistic system to open and close the valves. There are several possible ar rangements in Apistoconcha. First, it is assumed that the umbonal cavities represent points for muscle insertion. They have smooth s hell ultrastructure and no other area on the interior appears to represent muscle scars. If interpreted correctly, these insertion areas are remarkably
176
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
1 77
Fig. 117. Apistoconcha aphe/es Conway Morris, gen. et sp. nov., ventral valves. Horse Gully, Parara Lst., 6429RS109 (A,B), UNEL1854 (C,D,F,G), 6429RS108 (E,H). All x60 except H (x90). A, SAMP30775, anterior view of interior. B, SAMP30776, interior view. C,D, SAMP30777. C, interior view of posterior region. D , exterior view. E , SAMP30778, interior view. F , SAMP30779, interior view. G , SAMP30780, anterior view of interior. H, SAMP30781, posterior view.
deep, but a possible analogy may exist in the sowerb y e l l i d s . Th i s group of a r t i c u l a t e brachiopods has adductor impressions in the form of deep conical cavities on the ventral valve (Spjeldnaes, 1957). Sets of muscles running be tween the umbonal cavities of the dorsal and ventral valves (Fig. 115) could act as adductors. Possible location of the antagonist to this system is debatable. If, as in articulate brachio-
pods, there were diductor muscles, then one pos sibility is that the umbonal cavities housed other muscles that ran across the body cavity to insert into the posterior pits. Those that arose from the dorsal umbonal region converged on the median pit on the ventral valve, while the set originating from the ventral umbonal cavities inserted into the pair of posterior pits on the dorsal valve (Fig. 115). Such an arrangement might have the
Fig. 116. Apistoconcha aphe/es Conway Morris, gen. et sp. nov., dorsal valves. Horse Gully, Parara Lst., 6429RS108 (A,B), 6429RS109 (C-F), UNEL1854 (G-K,M), UNEL1 762 (L). A,B, SAMP30768. A, interior view, x40. B, oblique view, x40. C-E, SAMP30769. C, posterolateral view of exterior, x60. D, anterior fold, x200. E, interior view, x60. F, SAMP30770, anterior view, x60. G-I, holotype, SAMP30771. G, anterior view, x90. H, posterior view, x90. I, interior view, x90. J, SAMP30772, posterolateral view, x60. K-L, SAMP30773. K, anterior view of interior, x90. L, posterior view, x60. M, SAMP30774, detail of anterior fold, x200.
178
STEFAN BENGTSON et al.
desired result of opening th� valves, with the line UNEL1854, 1762) and Kulpara (UNEL1860B, of action lying posterior to the hinge line and . C), Parara Lst.; Mt. Scott Ra., Ajax Lst. (UNE aligned at a steep angle to the plane of n;)tation L1876). of valve opening. An altermitive suggestion is that the antagonist Diagnosis. Anterior margin of ventral valve en to the adductor muscles was ligamentary, per tite, lacking sulcus. Dorsal valve has stronger haps formed of decalcified shell, and located in anterior ridges and more subdued posterior folds the region of the posterior pits. Spjeldnaes (1957) than in A. siphonalis. �uggested that in some articulate brachiopods a ligament acted as a substitute 'for highly ineffi Description. A. apheles is similar to A� sipho:.. cient diductor muscles. A third, nalis, with the exception that the anterior tyargin . and not necessarily exclusive, alternative is of the ventral valve (morph'b) is entire and lacks that valve opening was mediated via hydrostatic the prominent sulcus (Figs 117B,F, G, 118A-E). pressure involving distension of soft-bodied For the most part other differences seem minor, reservoirs such as a .feeding organ or some other . but the posterior folds of the dorsal valve (morph coelomic reservoir. In lingulid inarticulate a) appear less strongly developed (Figs brachiopods Trueman & Wong (1987) noted that 116A,C,E,F,I, 118F-J), while the anterior ridges coelomic pressure substitutes for the cla.ssic an on the interior of this valve seem to be propor tagonists (elastic ligament or didudor muscles), tionally stronger (Figs 116B,D,H,I,K,M, 118G although they stress that as'yet no decision has I). In other respects, including_ overall outline, b een t aken as to whether this coelomic relative convexity, articulating teeth that alter mechanism is primitive to the Brachiopoda or an nate in position in the ventral (Figs 117A-G, 118A,E) and dorsal (Figs 116A,B,E,F,G-I,K, adaptation to bUITow:ing. . This hypothetical reconstruction leaves unex 118G-I) valves, poste rior pits (Fig. 117D,G), plained the function of the anterior cavity on the and umbonal and anterior pits (Figs 116A,B,F, dQrsal valve, assuming that it too acted as a point 118G), A. apheles is similar to A. siphonalis. for tnuscle insertion. Depending on its opposite point of insertion, it could have acted as either an Comparisons. A. apheles occurs str�tigraphical obliquely orientated adductor muscle or as. a ly below the similar species A. siphonalis in the highly inefficient diductor, but in either case it Horse Gully section, and may be its direct ances would have to transverse the area believed to tor.· have housed the feeding cavity . An alternative, entirely.hypothetical, interpretation is that by Biology and ecology. The mode of life of A. insertion into soft tissues, contraction of this apheles probably resembled that of A. siphona muscle could help to protrude either the feeding lis. Absence of an anterior sulcus may have l�d organ or other parts of the body, to expel water to a less efficient separation of inhalent and ex halent currents, -but. a stronger development of and cleanse the feeding chamber. the anterior ridges may have compensated. Apistoconcba apbeJes ConwayMorris, sp. . Apistoconcha celsa Conway Morris, sp. nov . novo (Figs 116,117;118A-J) . ' (Fig. 118K-P) Etymology. Greek apheles, smooth, on account Etymology. Latin celsus, high, referring to the of the lack of an anterior sulcus. . steeply inclined valves. Material. Holotype SAMP30771 (Fig. 116G-I) . from UNEL1854; 22 figured paratypes and c. Material. Holotype SAMP30789 (Fig. 118K, L); 3 figured paratypes and 5 other specimens, all 100 other specimens. from the Parara Lst. at UNEL1856 in Horse Gully. Distribution.' Horse Gully, (6429RSI07-109, -
.
.
-
Fig. 118. Apistoconcha apheles Conway Morris, gen. et sp. novo (A-J) and Apistoconcha celsa Conway Morris, gen. et sp. novo (K-P), ventral (A-E), dorsal (F-J) and indetenninable (K-P) valves. Horse Gully, Parara Lst., 6429RS107 (A-J), UNEL1856 (K-,-P). A, SAMP30782, anterior view of interior, x40. B,C, SAMP30783. B, anterior view of exterior, x40: C, lateral view; x40. D, SAMP30784, exterior view, x40. E, SAMP30785, anterior view of interior, x60. F,G, SAMP30786. F, anteriorview of interior, x40. G, lateral view, x40. H,I, SAMP30787. H, interior view, x60. I, pos.terior view, x60. J,. SAMP30788, lateral view of exterior, x60. K,L, holotype, SAMP30789, steinkefn:-K., anterior view, x60. L, lateral view, x60. M, SAMP30790, steinkern, lateral view of exterior, x60.-�N;O� SAMP30791, steinkern. N, lateral view, x60. 0, weak polygonal pattern representing possible shell ultrastI1i<;ture, x200. 'P , SAMP30792, steinkern, posterior view, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
179
180
.
STEFAN BENGTSON etal.
Diagnosis. Valves steep and somewhat conical.
.
Description. This species is rare, and valves are poorly preserved. Some specimens represent in tact shell, albeit phosphatized (Fig. II8M). Ex ternal concentric structures probably represent growth increments. Internally, articulating teeth can be identified, but are poorly preservfd. Steinkerns show that the interior had steep mar gins and overall a rather conical shape, capped by a pair of umbonal cavities (Fig. 1I8K,L,N). The precipitious "interarea consists of two obli quely orientated faces, meeting along the midline and sometimes forming a crest (Fig. 1I8P). On the steinkern surface a faint, crudely polygonal pattern (Fig. 1180) may reflect shell ultrastruc ture.(cf. Runnegar, 1985b, fig. ID,E). Fragments ofa sheet-like structure adhering to the steinkern (Fig. II8N,P) may represent phosphatized shell. No information on possible posterior pits, anterior ridges, or other structures is available. Comparisons. At Horse Gully A. celsa strati� graphically precedes A. apheles .and may be an cestral. Scarcity of suitable material precludes detailed comparisons, but A. celsaappears to . differ most strikingly in the steepness of the valves. In addition, the ?polygonal �hell ultrastructure appears restricted to A. 'celsa and' may indicate a difference irFshell arrangement. Otherwise, its mode of life is inferred to be similar to thatofA. apheles andA. siphonalis. Apistoconcha sp. indet: Material. SAM P 3 0 9 8 7 , 30988 from UNEL17 6 3B, Cu r r a m u l k a, Pa r a r a L s t .; SAMP30985, 30986 from UNEL1764, north of Bunyeroo Creek, Flinders Ra., Oraparinna' Shale; SAMP30989, 30990 from"'UNELI872, .' . Mt. Scott Ra., Ajax Lst. Description� Apistoconchg, o c c u r s i n th ree horizons where paucity of specimens combined with incomplete preservation precludes confi dent assignment to known species. Spe"cimens from (UNEL1763B) may be amongst the oldest k nown occ urrences, 'perhaps equivalent to UNEL1856 (base of the Parara Lst. at Horse Gully) which yields A. celsa. Two specim�ns preserved in glauconite from UNELI872 conslst of a dorsal and ventral valve, respectively. The former has a well preserved hinge area, but the latter specimen is incomplete anteriorly, so a sulcus cannot be confirmed. Specimens from UNEL1764 (base of the. Oraparinna Shale at Bunyeroo Gorge) are amongst the youngest ex amples· froin Australia. Specimens are not well preserved, but in one of the two .dorsal valves
teeth are v isible, wh ile the other s h ows prominent posterior folds. No ventral valve nis sufficiently comple�e to reveal any anterior sul cus. Stratigraphy ofAPISTOCONCHA spp.
tn the Parara Lst. at Horse Gully,A. celsa occurs at the base (UNEL1856), A. apheles in the first well-exposed beds 18m higher (6429RS107, U N ELI8 54, U NEL1 7 6 2 ( a p p r o xim a t e ly equivalent to 6429RSI08 and 6429RS109), and A. siphonalis near the t o p of the foe ction (UNELI852). The transition between A. celsa and A. apheles is not exposed. However, transi tion from A. apheles to A. siphonalis is abrupt, occurring in 1 metre of section. Biostratigraphic utility of this event deserves consideration. Thus, in the Parara Lst. at Kulpara, UNEL1860B and C withA. apheles, may be correlated with a level no higher than UNEL1854 (and equivalent UNELI762 and 6429RSI08-109) at Horse Gully. Similar arguments presumably apply to A. apheles in the Ajax Lst., Mt. Stott Ra. (UNEL. 1876). Evolution. The abrupt transition fromA. apheles toA. ,siphonalis appears to. have peen a pseudo extinction in as rrilich 'as A. apheles does not co-occur with its descendant. The development of a prominent sulcus, and posterior folds may have' been trivial in genetic terms, specified by proliferation of growth cells at three points on the margin. A functional explanation in terms of enhanced separation of the water currents was offered above. It could be speculated that development of the posterior folds was pleio tropically linked to sulcus growth, and may not have been of direct benefit. Affinities. Apistoconcha and presumably Tian-: zhushanella invite closest comparison with brachiopods, especially because of valve sym metry. In common with articulate brachiopods, the valves hinged with teeth, and opening and closure of the shell, may have been medi�ted by an antagonistic system of muscles (Fig. 115). Liu (1979) included Tianzhushanella within the Brachiopoda, but such a placement for either this genus or Apistoconcha is debatable. Although v a l v e s of Apistoconcha have a prominent . posterior face (Figs 108H, I16L, 117H) similar to the interarea of some articulates, their overall shape finds no counterpart in any known brachiopod. Moreover, the system of articulatory teeth differs from articulates where the teeth articulate with distinct sockets . on the opposite valves. The - hypothetical arrang�ment of the musculature differs' from thatof br�l�hiopods,
EARLY CAMBRIAN FOSSILS, S. AUST.
and direct homologies of the diductors are dif ficut to establish. Aroonia Bengtson, gen. novo [SB] Etymology. From Aroona Creek, near the Mt. Scott Ra., type region of Aroonia seposita. Type and only species. Aroonia seposita sp. nov. Distribution. Australia, Lower Cambrian. Diagnosis. Bivalved, biconvex, plane of bilateral symm etry through midline of each valve. Posterior margin almost straight. One valve (pit valve) with median pit formed by internal diver sion of posterior margin to form small enclosed conical space; opposing valve (boss valve) with boss-like callosity in corresponding position. Shell surface smooth, sometimes with weakly expressed growth lines. Shell probably cal careous.
Aroonia seposita Bengtson, sp. nov. (Figs 119-123) Etymology. Latin sepositus, apart, distinct, refer ring to the unique nature of the species. Material. HolotypeSAMP30796(Fig.121A-G) from the Ajax Lst. at UNEL1871 in the Mt. Scott Ra.; 14 paratypes. Distribution. Curramulka, Parara Lst. (UNEL 1848, 1849, 1851); Mt. Scott Ra., Ajax Lst. (UNEL1871, 1872). Diagnosis. As for the genus.
181
bonal overhang, this creates a semirounded out line of the shell broken by the posterolateral ears (Figs 119A, 122A). Both valves are externally smooth, sometimes with faintly expressed concentric growth lines (Fig. 120A, 121A,H, 122A,F), the fine structure of which consists of fibres about 1f.Lm thick, radiating from the umbo (Figs 119F,G, 120E). Although clearly reflecting original structure of the shell, the fibrosity is seemingly dependent on preservation. Its presence in specimens from UNEL1872 (Figs 119, 120), but not in those from UNEL1871 (Figs 121, 122), is probably related to diagenesis of the mineral and/or organic com ponent of the shell. The pit valve (Figs 119, 121) has a narrow interarea-like field formed by the growing posterior margin and usually with distinct growth lines (Fig. 121E,N). The characteristic median pit is formed by an internal diversion of the shell to enclose a conical space with an apertural diameter of about 25-30 f.Lm (Figs 119B,E,I,L, 121C,F,G,J,K). Although this space may be closed to the exterior (Fig. 121N), many specimens have a more or less pronounced slit in the' interarea' , widening with growth and expos ing the side of the conical space to the outside. However, the ragged edges of the slit hint that originally it was covered with a thin shell, and that its present form results from incomplete preservation. The conical space appears to end blindly against the inner side of the shell, open ing neither to the inner nor outer side. On the boss valve (Figs 120, 122), there is a corresponding median boss (Figs 120B,E,F, 122B,C,D,G,I,J,K,L,N,Q). The interarea is nar rower than that of the pit valve, and the boss is a low callosity on the inner side, often separated from the outer part of the shell by a narrow trough (Fig. 120F, 122G,Q). Usually the boss is about 60-80J.Lm wide with a smooth lateral transition to the surrounding shell (Fig. 122D). In one specimen (Fig. 122I-L), however, it is only about 30f.Lm wide and flanked by two shallow depressions. A posterior gap between the valves occurs because although the posterior margin in the pit valve lies within the plane of commissure, the corresponding margin in the boss valve makes a shallow arch (Fig. 120C, 122F,P). There is no clear evidence of muscle at tachment surfaces or other structures on the inner side of the two valves.
Description. Two types of convex valves are interpreted as representing opposing units of a brachiopod-like animal. As no obvious com parison can be made with the dorsal and ventral valves of a brachiopod, the terms boss valve and pit valve (usually the more convex) are here used. This is not meant to ignore possible homologies, and in other respects brachiopod terminology and orientation is adhered to so far as possible. Both valves have a marginal umbo. No articu lated specimens have been found, but close agreement between the two valves with regard to size, commissural profile, structure, preserva tion, and occurrence leaves little doubt that they articulated snugly. Discussion. Aroonia seposita agrees closely in Viewed perpendicular to the commissural plane, the shell is about as broad as it is long. The shell shape with a generalized brachiopod, but the median pit-and-boss structure does not posterior margin of the commissure is almost resemble any known structure within either inar straight, the median part being slightly posterior to the lateral parts. Together with a small um- . ticulate or articulate brachiopods. Although one
182
STEFAN BENGTSON etal.
Fig. 119. Aroonia seposita Bengtson, gen. et sp. nov., pit valves. Mt. Scot! Ra., Ajax Lst., UNEL1872. All x40, except where other wise stated. A,B,H, I, and L stereo-pairs. A-G, holotype, SAMP30793. E, pit in oblique lateral view, x400. F, detail of C, x200. G, detail of F, x2000. H-M, SAMP30794. L, detail of I, x400. M, pit in obl ique lateral view, x400.
EARLY CAMBRIAN FOSS I LS, S . AUST.
183
Fig. 120. Aroonia seposita Bengtson, gen. et sp. nov., boss valve. Mt. Scot! Ra., Ajax Lst., UNEL1872. All x40, except E and F. A and B stereo-pairs. SAMP30795. E, detail of C, x400. F, boss in oblique lateral view, x400.
specimen (Fig. 122I-L) has a boss of about the same diameter as the pits of the opposing valve, the boss is usually much wider than the pit. As there also appears to have been a gap between the two valves in this region, it is clear that the pit-and-boss formed no interlocking mechanism comparable to the teeth and sockets of articulate brachiopods. The median position would in any case have been unsuitable to prevent lateral slew ing of the valves, a major function of the articu late hinge (Rudwick, 1970; Jaanusson, 1971). One clue to their function lies in the fact that, as seen perpendicular to the commissure, the posterior margin of the two valves is not exactly straight, because the median part lies slightly behind the lateral ends. This is enough to bring the pit and boss behind the line that would serve as an axis of rotation if the two valves closed and opened in a fashion similar to that of articulate brachiopods. An elastic ligament or a muscle running from the bottom of the pit to the boss might provide enough force to rotate the valves about this axis (Fig.123). With this model, however, the function of the boss is not clear, as it does not appear to change the angular momentum of the mechanical sys tem, but only to shorten the muscle or ligament. Although muscular platforms in brachiopods often have just this function (Rudwick, 1970, pp.62 -68), it is not easy to explain why the muscle or ligament would be recessed into a pit at one end and attached to an elevation in the
other. It is of course possible that the opening of the shell involved more complex movements following initial simple rotation, and that this could explain why the posterior gap is so large that it would have to be partly bridged by the boss. The structure of the pit suggests that soft tissue within it was attached to a fixed point and sub sequently did not change position with con tinuing growth of the shell. A fold of the shell-secreting mantle enclosed this tissue to form the conical structure that kept pace with the posterior shell margin. Although the slit in the 'interarea' (e.g. Fig. 119L) could indicate that soft tissue was attached to the external surface of the shell (and thus would be better interpreted as an extra-epith el ial l igament rather than a muscle), the fact that this 'interarea' may oc casionally be unbroken behind the pit (Fig. 121N) is evidence that secreting mantle tissue also lay outside the soft parts of the pit-boss system). Other functional explanations of the pit and boss may be based on the assumption that there was no direct connexion between the two struc tures. Thus the pit might house an attachment structure that emerged between the valves towards the exterior, and the boss might instead connect with an internal muscle system. It is difficult to evaluate the probability of these hypotheses, but it seems that relating the pit and boss to the same functional apparatus is less
184
STEFAN BENGTSON et al.
Fig. 121. Aroonia seposita Bengtson, gen. et sp. nov., pit valves. Mt. Scot! Ra., Ajax Lst., UNEL1871. All x60, except where otherwise stated. F and G stereo- pairs. A-G, holotype, SAMP30796. C, pit in oblique lateral view, x600. E, detail of D, x600. G, detail of F, x600. H-N, SAMP30797. K, pit in oblique lateral view, x600. N, detail of N, x600.
far-fetched. In particular, it seems to be impos sible to relate the pit to an organ similar to a
regarded as true brachiopods, it seems possible that they shared common anc estors. BraGhio
brachiopod pedicle, as it would then have to end blindly against the shell surface at all stages of ontogeny.
pods evidently evolved f rom a soft-bodied lophophorate worm that had at least some similarities with phoronids, but there is d iver
Discussion [SCM, S8J
gence of opinion as to whether the acquisition of skeletal valves in the various Lower Cambrian
Even though Apistoconcha and Aroonia are not
brachiopod orders was independent (Valentine, 1973; Wright, 1979; Goryansky & Popov, 1986)
EARLY CAMBRIAN FOSSILS, S. AUST.
185
Fig. 122. Aroonia seposita Bengtson, gen. et sp. nov., boss valves. Mt. Scot! Ra., Ajax Lst., UNEL1871. All x60, except where otherwise stated. A,8,L stere o-pairs. A-G, SAMP30798. D, detail of C, x500. G, boss in oblique lateral v iew, x500. H-L, SAMP30799. J, detail of I, x600. L, detail of K, x300. M-Q, SAMP30800. Q, boss in oblique lateral view, x300.
or monophyletic (Row ell, 1982). Even if the latter view commands acceptance, the markedly different valve morphologies of Apistoconcha and Aroonia indicate that during initial diver-
sification of lophophorates, acquisition of dorsal and ventral valves i nvolved a variety of short lived groups. The Inarticulata are more heterogeneous than
186
STEFANBENGTSON et al.
HYOLITHELMINTHS [SB]
A
Fig. 123. Aroonia seposita Bengtson, gen. et sp. novo Diagram to show proposed function of posterior pit and boss as attachments for diductor muscle or liga ment (small striated band). Shell black; pit valve below, boss valve above, posterior to the right. Star indicates position of hinge axis of shell; adductor muscle (large striated band) and other soft parts (light grey) hypothetical. A, closed shell. B. open shell
the Articulata, and as generally circumscribed may be neither holo- nor monophyletic (Wright, 1979; Goryansky & Popov, 1986; Rowell, 1982). In a wide sense,Apistoconcha andAroonia could then be referred to as inarticulate brachiopods if it could be shown that they are descendants of the same stock. Rowell's (1982) list of synapomor phies shared by ma jor brachiopod groups ap pears to be insufficient in this respect, however. Of the seven uniting all groups only - develop ment of ventral and dorsal mantles, and develop ment of setae at mantle margin are recog nizable in fossils, and only the former is demon strably present in Apistoconcha and Aroonia. Assignment of these Australian and Chinese taxa to the lophophorates implies that their evolutionary divergence was even greater than already apparent from the maj or brachiopod radiation (Wright, 1979; Rowell, 1982). How ever, the suggestion that the bivalved condition of Apistoconcha and Aroonia are products of convergent evolution from other soft-bodied an cestor must be regarded as a viable alternative.
Early Palaeozoicelongated, phosphatic tubes are commonly referred to the Hyolithelminthes Fisher, 1962. The original diagnosis of this order (Fisher, 1962, pp. W130, W132), as well as the original description of Hyolithellus (Billings, 1 871, pp.215,216,240, fig. 1 :3), referred to oper cula with paired muscle scars. There is, how�ver, no correspondence in occurrences and size'ran ges ofthe tubes (Hyolithellus and Torellella) and the flattened shells (Discinella and Mobergella) that are their presumed opercula (Bengtson, 1968; Missarzhevsky & Mambetov, 1981). Con sequently, hyolithelminths may be regarded as having l acked a mineralized operculum. The simple tubular morphology has encour aged form taxonomy; the namesHyolithellus and Torellella frequently being applied to tubes of circular and flattened cross-sections, respec tively. Such assignments are often on fossils whose preservation precluded observation of morphological and structural details or of the mineralogical composition. Moreover, even when the tubes are clearly primarily phosphatic, there seems to be a considerable variability in original structure and morphology. Studies of tube structure and composition would help to clarify hyolithelminth taxonomy, and would. also be of paramount importance to understanding the animals. The few detailed studies available have not indicated uniformity among hyolithelminth tubes. Wet chemical analysis of Hyolithellus micans tubes from the Middle Cambrian Kalby Marl of Bornholm indicated chitin and protein but no phosphate (Poulsen, 1963; Carlisle, 1964). Given the unconsolidated nature of the sediment (Berg-Madsen, 1981), contamination seems possible. Hurst & Hewitt (1977) inves tigated a fractured specimen of Hyolithellus micans from the glauconitic Lower Comley Sandstones (Ab4 of Cobbold, 1921), before and after etching with dilute HC!. They reported an inner granular layer (15/-Lm thick) with faint traces of parallel lamination, and a much thinner outer (3�Lm) layer of prisms of apatite subdivided into elongate spicules and granules. They com pared this latter layer to vertebrate enamel, but Hewitt (1980, p. 663) later acknowledged that it might have recrystallized. Grigor'eva (1980; in Grigor'eva & Zhegallo, 1979) investigated frac tured specimens of H. tenuis and T. lentiformis from middle Tommotian l imestones of the Lena River. She found that the tube wall in both taxa has two layers, each about 10--30/-Lm thick. The inner layer is finely laminated (laminae less than 0.5/-Lm thick).
EARLY CAMBRIAN FOSSILS, S. AUST.
The outer layer was interpreted as composed of chevron-shaped lamellae similar to those formed by the collar gland of serpulid polychaetes, but this structure is not convincingly displayed in the available figures. Phosphatic tubes occur in several Australian samples, but are often fragmentary and offer few possibilities for detailed morphological studies. Other samples, in particular from Curramulka, contain well preserved Hyolithellus and Byr onia? A preliminary structural investigation of H yolithellus is promising enough to warrant fur ther investigation. Hyolithellus Billings, 1871 *1871 Hyolithellus Billings, p.240.
Type species. Hyolithes micans Billings, 187 1 . Other species. H. acuticostatus Meshkova, 1969; H.filiformis sp. nov.; H. grandis Missarzhevsky, 1969;H.? infundibuliformis Meshkova, 1969;H. insolitus Grigor eva, 1982;H. rectus Mambetov, 1981;H. sinuosus Cobbold, 192 1 ; H. tenuisMis sarzhevsky, 1966;H. vitricus Mambetov in Mis sarzhevsky & Mambetov, 1981; H. vladimirovae '
Missarzhevsky, 1966.
187
lel lineations almost verticaJ in the figure are polishing scratches). The laminae are fibrous, with parallel fibres c. 0.05-0.1 ,,"m in diameter. Adjacent lamellae have different directions of the fibrosity (Fig. 124D). Optical observations show that the tubes are built up of birefringent apatite, with c-axes oriented perpendicular to the tube surface.
Comparisons. The tubes agree with H. micans as applied in the literature. However, the characters of this species have not been thoroughly inves tigated, and until detailed study has been made of topotype material_ assignments to H. micans are tentative. H. vitricus Mambetov (in Mis sarzhevsky & Mambetov, 1981), from the Chulaktau and Shabakty Formations of Maly Karatau, Kazakhstan, is characterized by a smooth exterior surface with occasional weak growth lines. Dimensions and shape are similar to those of the specimens described herein. It is not possible t o conclude t owhich, if either, ofthe two mentioned species the Australian specimens should be referred. The tentative assignment to H. micans may be potentially less misleading, because of the broad interpretation of this species.
Australia, Antarctica; Lower-Middle Cambrian.
Hyolithellus filiformis Bengtson, sp. novo (Fig. 125)
Diagnosis. Phosphatic, laminated tubes, low rate
Etymology. Latin filiformis, thread-like; for the
of taper, circular in cross-sectio n . Surface smooth or with simple growth lines.
shape of the tubes.
Distribution. North America, Europe, Asia,
Hyolithellus cf. micans(Billings, 187 1)(Fig. 124)
Material. Holotype SAMP30804(Fig. 125B, C), from UNEL1846 (Curramulka, Parara Lst., 'trilobite bed'); c. 20 paratypes.
Material. Approximately 200 specimens.
Distribution. Curramulka (UNEL1846, 1763B)
Distribution. Horse Gully, Kulpara and Parara
and Horse Gully (UNEL1852), Parara Lst.; Mt. Scott Ra., Ajax Lst. (UNEL1866, 1867, 1873).
Lsts (6429RSI03-4, UNEL1852, 6429RS114); Curramulka, Parara Lst. (UNEL1845-1848, 1763B, N MVPL95); Kulpara, Parara Lst. (6529RS99-104, 6529RS 1 13); Mt. Scott Ra., Ajax Lst. (UNEL1865, 1870, 1873).
Description. Tube fragments are straight, up to 2.2mm long and 0.5mm wide, but piecesofwider tubes are also present. The angle of divergence is c. 5'. The wall is 4-30,,"m thick. The surface is smooth, with weakly expressed and irregularly spaced annulations. A tangential section through a thick-walled specimen (Fig. 124E,F) reveals the wall to be made up of thin laminae approximately paral lel to the surface(the parabolic pattern in Fig. 124E is due to a slightly oblique section and the paral-
Diagnosis. Hyolithellus with narrow, winding tubes,I00-150,,"m in diameter, divergence angle of 0-1.5'. Regular growth annulations about 5075,,"m apart.
Description. The narrow tubes (100-150,,"m diameter) have an angle of divergence of 0_1.5'. They are curved (Fig. 125A,G) or bent (Fig. 125B,D) in variable directions; but some frag m e n t s m ay be straight for at l e a s t I m m (Fig.125E). The outer surface has pronounced, regular annulations as terraced steps, c. 5075,,"m apart (Fig. 125C,F,H). The direction of the terrace edges in relation to the aperture is not clear. [f the terraces represent terminations of growth lamellae stacked from
188
STEFAN BENGTSON et al.
Fig. 124. Hyolithellus cf. micans Billings, 1871. Curramulka, Parara Lst., UNEL1846. A,B, SAMP30801. A x40. B x120. C-F, SAMP30802. C,D, x40. E, tangential section (polished and etched ) through wall, x480. F, detail of E, x4800.
inside the tubes, one might predict the edges to face towards the aperture, so that Fig. 125 is oriented orthodoxly. Some specimens (Fig. 125B,D), however, decrease slightly in diameter towards this end. Others (Fig. 125A,E) increase in width towards this end (although the direction of the terrace edges is not clear in Fig. 125A) and a n o t h e r m a i n t a i n s a u n i fo r m d i a m e t e r throughout (Fig. 125G). Thus the terraces or direction of divergence (or both) are unreliable indicators of growth direction.
Comparisons. The Australian species is remi niscent of Hyolithellus? sinuosus Cobbold, 1921, described from a few fragments from the Lower
Comley Sandstone (horizon Ab} ) of Cwms, near Comley, Shropshire. The only figured specimen (Cobbold, 1921, p1.24, fig.24) has a diameter of c. 200fJ.m, and according to the accompanying description the tubes are curved in more than one plane, have a dull grey surface, and in one case shows distinct, evenly spaced annulations. Cob bold & Po cock (1934, p.321, p1.40, fig A) intro duced H(?) tortuosus for similar tubes from the Acrothele prima Shale of Rushton, Shropshire, without reference to H (?) sinuosus. Brasier (1984, p.236) synonymized H(?) sinuosus (and, tentatively, H(?) tortuosus) with his 'H. cf. micans Morphotype A' from the Home Farm Member of the Hartshill Formation in Jee's
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig.
lS9
125. HyolithellusjUiformis Be ngtson, sp. novo Curramulka, Parara Lst., UNELlS46 (A-F), and Mt. Scot! R a., Ajax Lst., UNELlS67. All xSO, except B,C,F, and H. G, stereo-pair. A, SAMP30S03. B,C, holotype, SAMP30S04. B, x 100. C, detail of B, x240. D, SAMP30S05. E,F, SAMP30S06. F, detail of E, x240. G,H, SAMP30S07. H, detail of G, x240.
190
STEFAN BENGTSON et al.
Quarry, Nuneaton, Warwickshire. The form was not extensively illustrated, but Brasier remarked that it was relatively large, attaining a diameter of 1.7mm. As H. flU/ormis is characterized by a smaller (1 00-1 SOf,Lm) diameter and at most slight expan sion of the tube diameter at this size,we conclude that it does not represent small specimens of a larger form.
may have been partly embedded in the sediment. Both species are interpreted as low-level suspen sion feeders. Byroni a Matthew, 1899 *1899 Byronia Matthew, p.41.(For further synonymy see Bischoff, 1989)
Type species. Byronia annulata Matthew, 1899. Biology.Biomechanically, tubes of H. cr. micans and H. flU/ormis may be regarded as smooth. Even in annulated specimens of H. flli/ormis, maximum relief of the 'terraces' is <4f,Lm (Fig. 12SC). This is below the normal relief of terrace lines providing directional friction in burrowing organisms, because the height of such terraces is generally within an order of magnitude of the prevalent sediment grain size and is not related to the size of the animal (Savazzi, 1986). The terrace lines in these small Hyolithellus may be n othing more than surficial expressions of growth lamellae. Some hyolithelminths and anabaritids (see below), however, have well developed annular ridges or flanges. For example, Hyolithellus isiticus has aperturally directed flanges about SOf,Lm high (Rozanov etai., 1969, p1.7,figs 1,17) that may have served to anchor the tube in muddy sediment. In the absen�e of a constructional con straint on the development of annulated flanges or terraces in hyolithelminth tubes (the terraces are simple modifications of the growth rings), there may be a correlation between annulation relief and type of infaunal life (see also Hurst & Hewitt, 1977, p. ISO). The stacked fibrous lamellae in the wall of H. cf. micans resemble the 'plywood structure' of arthropod cuticles (Wainwright et aI., 1976), which is well designed to withstand mechanical stress, because a breakage pattern developed in one lamella will not readily propagate to the adjacent ones. A mechanically resistant wall sug gests protection against high water energy and/or predators. In burrowing bivalve molluscs thicker shelled forms are conspicuously restricted to the shallowest sediment levels (Stanley, 1970, p.68). The variable growth vector of H. flU/ormis suggests that either it was compet�ng for space with other organisms or its position in or on the substrate was not stable. In the absence of evidence for dense thickets of tubiculous organ isms in the Parara Lst., it seems possible that H. filiformis was lying on or partly in a soft sedi ment, where it was occasionally disturbed by currents and the activity of other animals. H. cf. micans may have lived in a more upright posi tion, judging from its nearly straight tubes. No attachment structure is preserved, and the tubes
Distribution. North America, Europe, Australia; Lower Cambrian-Lower Devonian. Byroni a? sp. nov. A (Fig. 126)
Material. SAMP30808, 30809 and hundreds of fragmentary tubes. Distribution. UNEL1846, 1847, 1763B, Cur ramulka, Parara Lst., UNEL1868, 1870, 1873, Mt. Scott Ra., Ajax Lst. Description. Tubular fossils with a lenticular cross-section. The slightly expanding proximal end has a smooth margin that was probably used for attachment to a hard substrate. Distally the tube is deeply split along the broader sides. Remarks. These fossils appear to represent ses sile tube-d welling or ganisms w ith partly mineralized tubes. Bischoff (1989) included a number of similar Cambrian-Devonian fossils in his Order Byroniida, suggesting that the early Palaeozoic Phosp hannulus Muller et al., 1974 known as an epizoan on crinoids (WerIe et al., 1984) may be a junior synonym of Byronia. Bischoff (1989) interpreted byroniids as thecate scyphopolyps. Relationships .with hyolithel minths such as Hyolithellus and Torellella are not clear at present.
ANABARITIDS [SCM, SB]
.
The apparent restriction of tubicolous, triradial anabaritids to the lower part of the Tommotian (including the Manykay or Nemakit-Daldyn horizon) of Siberia (Missarzhevsky, 1982) has led to widespread assumption that other occur rences must be of equivalent age. Many such correlations may be defensible, but the recogni tion here of Australian anabaritids in strata of Atdabanian age suggests that by themselves anabaritids are not reliable biostratigraphfc in;. dicators. Although Anabarites was only erected . in 1969 (Missarzhevsky in Voronova & Mis sarzhevsky, 1969), Rosen (1919) had described anabaritids from Cambrian l imestones in
EARLY CAMBRIAN FOSSILS, S. AUST.
191
Fig. 126. Byronia? sp. novo A, Curramulka, Parara Lst., U NELl846. A, SAMP30808, x50, stereo-pair. B,C, . SAMP30809. B, x50. C, xlOO.
Sweden, but had not erected a formal taxonomy (Qian & Bengtson, 1989). Jiang's claim (in Luo et al., 1982, p. 170) that a fossil from Meishucun described by Wang (1941) as 'Hyolithes sp. type a' is Anabarites appears dubious. Val'kov (1982) assigned anabaritids to four families that, taking into account more recent additions, house at least 13 nominal genera: Aculeochreidae (Aculeochrea V a l ' k o v & Sysotv, 1970; Jakutiochrea Val'kov & Sysoev, -1970); Anabaritidae (Anabaritellus M i ssar zhevsky, 1974; Anabarites Missarzhevsky in Voronova & Missarzhevsky, 1969; Cambrotu bulus Missarzhevsky in Rozanov et al., 1969; Udzhaites Vasil'eva, 1986; Kotyikanites Bok ova, 1985; Kotuites Missarzhevsky, 1989), An gustiochreidae (Angustiochrea V a l ' k o v & Sysoev, 1970; Gastreochrea Val'kov, 1982; Mariochrea Va I' ko v , 1982; Selindeochrea Val'kov, 1982), and Lobiochreidae (Lobiochrea Val'kov & Sysoev, 1970; Longiochrea Val'kov & Sysoev, 1970). Tiksitheca Missarzhevsky in Rozanov et aI., 1969, is often included in this roster, and may even be synonymous with
Anabarites.
However, Landing's (1988) asser tion that it is a senior synonym is invalid on grounds of priority (Anabarites Missarzhevsky in Voronova & Missarzhevsky, 1969 was pub lished in January, and Tiksitheca Missarzhevsky in Rozanov et al., 1969 i n Jun e or l ater. Anabarites was incorrectly indicated to be new in the latter publication). Distinction between at least some genera and respective familial assignments seems to be in need of reappraisal, but existing illustrations make it difficult to verify proposals (see below). One potential problem is linked to preservation. Thus, some taxa are known from steinkerns, but ostensibly different taxa are recognized on the basis of relatively complex external walls. Mor� phological variability at specific levels has also received insufficient attention, and the large number of nominal species (c. 36) probably over estimates known diversity by a considerable margin. Anabaritid records are complicated further by possible misassignments. For example, Mesh kova (in Repina et aI., 1974, p1.19, fig.7) at-
192
STEFAN BENGTSON et al.
tributed a probable anabaritid from the Tam matian of Siberia (Kharaulakh;Tuora-sis ridge) to the tubiculous Coleolus trigonus (Sysoev, 1962, figs 12-14;Missarzhevsky in Razanav et al., 1969, pl.7, figs 8,13,20). The majority afbonafide anabaritidgeneraare known only from the Siberian platform, where they appear to be restricted to the Tommotian or Nemakit-Daldyn horizon. Phylum, Class, Order, uncertain Family ANABARITIDAE Missarzhevsky, 1974 *1970 Aculeochreidae Val'kov & Sysoev, p.98. *1970 Angustiochreidae Val'kov & Sysoev, p.96. 1*1970 Lobiochreidae Val'kov & Sysoev, p. 95. *1974 Anabaritidae Missarzhevsky, p.186. [non Anabaritidae Glaessner, 1979b]
Designation of a new family by Glaessner (l979b) was the result of an oversight of Mis sarzhevsky (1974). However, Glaessner (I 979b) was correct to point out that if ICZN rules are followed then as the type genus isAnabarites, the erection of the Angustiachreidae by Val 'kav & Sysaev (1970) to house this genus, is invalid. Suppression of this name in favour of Ana baritidae was noted by Missarzhevsky (1974, p.186), who also considered the Labiachreidae Val'kav & Sysaev, 1970, and Aculeachreidae Val'kav & Sysaev,1970, synonyms. Given even these uncertainties, erection of a suprafamiliaJ taxonomic scheme seems inap propriate. Val'kav & Sysaev (1970) erected the Order Angustiochreida, but in view of the prob able synonymy of Angustiochrea and Anabarites (Glaessner,1979b), this is unsuitable. Val'kav (1982) used the Subclass Angustiamedusa of the Class Scyphozoa, but there seems to be no reason to accept the conjectured affinity to scyphozoan medusae or to refer to this particular name. Missarzhevsky's (1974) reference to 'Class and order incertae sedis' seems the most sensible procedure on present evidence. Anabariles Missarzhevsky in Voronova & Missarzhevsky, 1969 * 1969 Anabarites Missarzhevsky in Voronova & Missarzhevsky, p.209. *1970 Angustiochrea Val'kov & Sysoev, p.97.
*1985 Kotyikanites Bokova, p.16. *1986
Udzhaites Vasil'eva, p.104.
Type species. A nabarites trisulcatus M i s sarzhevsky in Voronova & Missarzhevsky, 1969. Other species. A. acuminatus Chen & Xiong in Xing et al., 1984b;A. com positus Missarzhevsky in Rozanov et al., 1969;A. gracilis Chen, 1984; A. grandis Val'kav, 1982; A. isiticus M i s sarzhevsky, 1974; A. longissimoides Chen & Xiang in Xing et al., 1984b; A. obliquasulcatus Qian, 1978a; A. primitivus Qian & Jiang, i n Jiang, 1980a [nomen nudum] (see Q i a n & Bengtsan,1989); A. rectus Vasil'eva in Rudav skaya & Vasil'eva, 1984; A. rotundus Qian, 1977;A. signatus Mambetov i n Missarzhevsky & Mambetav, 1981; A. sulcoconvex Q i a n , 1978a; A. ternarius Missarzhevsky in Rozanov et al., 1969; A. tricarinatus Missarzhevsky i n Rozanov et al., 1969; A. tripartitus Missar zhevsky in Razanav et al., 1969; A. tristichus Missarzhevsky in Rozanov et al., 1969; A. un dulatus Qian, 1978a. In addition, species presently assigned to Anabaritellus (A. hexasul catus Missarzhevsky, 1974;A. xishuiensis Qian, 1977); A. hariolus Val'kav, 1987; Angus tiochrea (A. lata Val'kav & Sysaev, 1970; A. rara Fedorav, 1984);lakutiochrea (1. convexa Val'kav & Sysaev, 1970; 1. lenta Bakava & Val'kav in Val'kav, 1987;1. portentosa Bakava & Val'kav in Val'kav, 1987;1. solita Val'kav, 1987);Kotyikanites (K. sulcatus Bakava, 1985; K. vallatus Bakava, 1985); Mariochrea (M. sinuosa Val'kav, 1982); Selindeochrea (S. tecta Val ' k a v , 1 9 8 2) a n d Udzhaites (U. mis sarzhevskyi Vasil'eva, 1986) appear also to be Anabarites(seebelow). Yin etal. (1980) referred trisulcate tubes from Maidiping, Sichuan to
Lobiochrea c f. natella (consistently misspelt notella), and this material may also be referred to Anabarites (status of type material of L. natel la Val'kav & Sysaev, 1970, is not discussed here, b u t n o t e above p r o b a b l e s y n o n y m y o f L a b i a c h r e i d ae w i t h Anabar i t i d a e (Mis sarzhevsky, 1974)). Zhang [Chen] (1977) il lustrated specimens of Anabarites from Shaanxi Province, China, as Trisulcatheca. Although he referred to Qian as author of 'T. trisulcata' and 'T. kueichouensis' (Zhang [Chen], 1977, p.123), these species do not appear to have been described elsewhere.
*1970 lakutiochrea Val'kov & Sysoev, p.98. *1974 Anabaritellus Missarzhevsky, p.l87.
Distribution. Lower Cam brian of northern
Trisulcatheca Zhong [Chen], p.119. [nomen nudum] *1982 Mariochrea Val'kov, p.69. *1982 Selindeochrea Val'kov, p.68.
(Olenek region, northwest slope o f Anabar Mas sif) and eastern Siberia (Aldan River and Uchur Maya region), Kazakhstan (Maly Karatau), South Australia (Yarke Peninsula,Flinders Ra.),
1977
EARLY CAMBRIAN FOSSILS, S. AUST.
northwest Canada (Mackenzie Mountains), China (including Hubei, Guizhou, Sichuan, Yunnan), Sweden, and Iran (B. Hamdi, pers. comm., 1986). Diagnosis. Elongate conical tube, generally moderate rate of expansion, tri-radial symmetry defined by internal keels arising from wall that may be smooth or bear peg-like projections. Areas between keels smooth or bearing median ridges of varying strength that confer hexa-radial symmetry. External ornamentation sometimes of prominent transverse ridges. Compa risons.Anabarites is not well understood. A plethora of species, many of which may be synonymous, are similar to the type species. Supposedly distinct genera, including Angus tiochrea, lakutiochrea, Mariochrea, Selin deochrea, Trisulcatheca, and Udzhaites may be synonyms of Anabarites. Minimal differences seem to separate Udzhaites and Anabarites. An gustiochrea and Mariochrea, possibly differen tiated on style of preservation (steinkern versus original wall), expand rapidly in diameter, but a r e o t h e r w i s e s i m i l a r to Anabarites, a n d GIaessner (1979b) proposed Angustiochrea as a junior synonym ofAnabarites.Anabaritellus and Selindeochrea have variably developed hexasul cate cross-sections, but the otherwise similar A. isiticus h as b e e n r e t a i n e d in Anabarites. Hexaradial variants probably arose several times from trifoliate ancestors, and all such species are provisionally assigned to Anabarites. lakutiochrea is treated here more extensively because it may have significant similarities to A. trymatus sp. novo lakutiochrea was erected by Val'kov & Sysoev (1970) for anabaritids having a rounded to triangular cross-section, and bear ing a characteristic series of projections on each of the three longitudinal keels that arose from the inner wall of the tube. Of the five species recog nized 1. tristicha,l. convexa, 1. lenta, 1. por tentosa, and 1. solita the first was assigned to Anabarites by Missarzhevsky (in Rozanov et a l.,1969, p.184). Moreover, apart from possibly 1. portentosa, these species (see Val'kov & Sysoev, 1970; Val'kov, 1987), are probably synonymous. Notwithstanding the opinion of Val'kov & Sysoev (see also Val'kov, 1975, 1982, 1987; Missarzhevsky,1983) thatlakutiochrea is justi fied, others (e.g. Matthews & Missarzhevsky, 1975; Sokolov & Zhuravleva,1983; Fedorov, 1984) referred to A. tristichus, a practice that is followed here. A. compositus is equally distinc tive, by virtue of its prominent rows of plate-like recesses or tabellae (Missarzhevsky in Rozanov et a l.,1969, p1.8, figs 5,9; Matthews & Mis-
-
193
sarzhevsky,1975, p1.2, figs 18, 19; piA, figs 10,11), but it has been retained in Anabarites. Hinz's (1987, text-fig. 31, p1.14, figs 37,38) as signment of tubes, having a triangular cross-sec tion with corners defined by prominent costae, to A compositus is regarded as questionable Chinese examples of A. tristichus (Qian, 1978a; Wang et al., 1984a; Xing & Vue in Xing et al.,1984b) might seem to offer further support to the argument above, but no illustrated material is sufficiently clear for convincing comparisons (see also Conway Morris & Chen , 1989). How ever, Chen (1984, p.55, pl.1, fig. 9,9a) illustrated steinkerns from Jijiapu, Hubei, of an ostensibly new species (A. gracilis), with a series of pits arranged along each furrow in a manner com parable to A. tristichus.
Anabarites trymatus Conway Morris & Bengtson, sp. novo (Fig. 127)
Etymology. Greek tryma, a hole or pit, referring to the series of pits along the longitudinal grooves of the steinkern. Material. Holotype SAMP3081 6 (Fig. 127K,L) from UNEL1852; 7 figured paratypes and C. 20 other specimens. Distribution. Curramulka (UNEL1845, 1846, 1763b) and Horse Gully (UNEL1852, 1853), Parara Lst. Diagnosis. Tubes elongate, 2.5mm or more in length. Internal keels bearing regular extensions. Keels absent during initial growth stage, giving interior of juvenile tube a circular cross-section. External ornamentation of fairly widely spaced transverse ridges. Description. The tubes are invariably incomplete phosphatic steinkerns, always lacking the proximal portion and almost certainly incom plete distally. Although the original wall has not been preserved, possible impressions are visible. The longest fragments are C. 2.5mm, although originally individuals may have been substan tially longer. The tube tapers p'roximally, but otherwise the sides are subparallel (Fig. 127A,B,D,K,N). Basally the cross-section is cir cular (Fig. 127E), but within a short distance narrow sulci appear and rapidly deepen to confer the characteristic triradial symmetry (Fig. 127J,L). Each of the three lobes so defined has a slight median depression, giving the tube a more subtle hexaradial symmetry. The three prominent sulci on the steinkern correspond to longitudinal keels arising from the
194
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
interior wall. Each sulcus is interrupted at fre- " quent and more or less equal intervals by deeper, lens-shaped depressions (Fig. 127C), marking" peg-like extensions that proj�cted inwards from each keel. " At" fairly regular intervals the steinkern bears low transverse ridges (Fig. 127A,D,F,G, H,K,O), that may correspond to annuli on the now absent wall. Much fainter transverse striations may- also�' occur between the ridges, perhaps representing impressions of finer growth increments. Other in dications o f shell ultrastructure on the steinkern surface were unproductive. However, infillings of endolithic borers (tunnels c. 4j..Lm diameter) occur occasionally (Fig. 127M), recalling slightly narrower excavations that Run negar (1985a) ascribed to endolithic algae, but differing in that they branch. More problemati cal, closely spaced, vermiform tubules (Fig. 1271) may also represent endoliths. Comparisons. Notwithstanding existing confu sion" on anabaritid taxonomy, A. trymatus ap pears to be closest toA. tristichus and the closely related A. conv!!xa, A. gracilis, A. lentus, and A. solitus. Points of comparison with "one or more of these taxa include a notched keel and slight hexaradial symmetry. A. trymatus differs from some of the northern Siberian material in tending towards more prominent sulci. However, mor phological variability in these species is not well known, and of three specimens of A. tristichus illustrated by Missarzhevsky (in Rozanov et al., 1969) one (their p1.8, fig.14) is similar to the Australian species (Val'kov,1987, pI.14, figs 9,10). Stratigraphic distribution.A. trymatus occurs in the Parara Lst. at Curramulka, where if is restricted to the lower part of the section. Rare occurrences near the top of the Horse Gully section (UNEL1852, 1853) in the same unit ap parently extend its range upwards. In Horse GullyA. trymatus co- occurs with the more abun dantA. sexalox, whereas at Curramulka it occurs alone.
Anabarites sexalox Conway Morris & Bengtson, sp. novo (Figs 128-131) Etymoiogy. Latin sex, six-fold, and Greek alox, furrow or groove; for the six-fold symmetry.
\
195
-, "
Material. Holotype SAMP30823 (Fig. 129A-E) from UNEL1856; 26 figured paratypes and C. 40 other specimens.
Distriby,tion: H o r s e G u l l y , P a r a r a L s t . (UNEL1852, 1853, 6429RS110, UNEL1854, 6429RS108, UNEL1761, 1856); Mt. Scott Ra., Ajax Lst. (UNEL1873, 1874, 1876, and possibly 1877). Description. In contrast toA. trymatus (andmany other anabaritids), the tube wall is frequently preserved (Figs 129A-E, 130L,N, 131A....:D), but its quality is widely variable so that only traces of the original wall, especially between the ex ternal ridges, may persist (Fig. 128E,H,I). The stein kern is often visible where the outer wall is locally absent, and in some specimens only the steinkern survives (Figs 128A-C,J, 129G-I,K,L, 131E,G). . Tubes are usually incomplete," consisting of mature stage sections with sub-parallel sides. Most complete specim�ns are juveniles (Figs 129A-D, 130A,B,L,N,Q,R), and the overall length attained is uncertain but exceeds 1.8mm. Mature width was typically 0.3�.35mm. " The proximal zone is short (c. 0.2-O.4mm) and lacks external annulations (Fig. 130A,B,L, Q,R). Often the most proximal region is reduced in diameter, giving the end of the .t\Jbe a teat-like shape (Fig. 129A,E). In one exceptionally preserved specimen, the rounded termination consists of three nodes or tubercles (Fig. 130M), one being somewhat larger (20 j..Lm across) than the other two (10j..Lm across). "These proximal nodes are set at 120°, and indicate that triradial symmetry was present from the inception of growth. Beyond this proximal zone the tube bears prominent annulations, witb a fairly regular spacing (Figs 128E,G, 129A, " 131A). They are slightly asymmetrical, gently inclined proximally (Fig. 131N),. "and" are separated by zones with irregular longitudinal striations" (Fig. . " 129B,C). Steinkerns show the proximal section of the interior to be smooth, with icircular cross-sec tion (Fig. 128J). This was succeeded by develop ment of three keels, in turn subdivided to give the six-fold division of the mature tube (Figs 128F,G,J,K, 129G-K, 131E-G). These new folds deepen rapidly initially," so in mature sec tions the six keels are equally developed, or the
Fig. 127. Anabarites trymatus Conway Morris & Bengtson,sp. nov. Curramulka,Parara Lst.,UNEL1845 (A�I), UNEL1763b (J); Horse Gully, Parara Lst., UNEL1852 (K-M), UNEL1853 �,O);A-C, SAMP30810, steinkern. A,B, x30. e, pits on sulcus, x400. D, SAMP30811, steinkern, x60. E, SAMP30812, proximal end, x90. F,SAMP30813, steinkerit,x90. G-I, SAMP30814,steinkern. G,x90.H,x60. I,possible endolithic.borers, x400. J, SAMP30815, steinkern, x90. K-M, holotype, SAMP30816, steinkern. K, x60. L; x90. M, possible endolithic borers, x600. N,O, SAMP30817,steinkern,x30.
196
STEFAN BENGTSON et al.
EARL Y CAMBRIAN FOSSILS, S. AUST.
original three may remain more strongly ex pressed. In transverse section the keels may show a slight basal constriction (Fig. 1301). In lon gitudinal profile the three keels that first appear during ontogeny bear somewhat irregular pegs (Fig. 131K,L), expressed in steinkems as a series of deeper pits within the grooves (Figs 128A, C,D,J,L, 1291). The other three keels, are smooth (Figs 128B, 129G,I). As in other anabaritids (Abaimova,1978; Val 'kov, 1982, 1987), the original composition of the wall is taken to be calcareous. The reason why the wall of this anabaritid has been phos phatized, whereas that of A. trymatus is never so preserved, is uncertain. However, replacement in A. sexalox is fin est in small juveniles and generally poorer in larger specimens approach ing in sizeA. trymatus. With questionable excep tions (Fig. 131H) no impression of ultrastructure occurs on steinkems, but a crude subradial fabric in the phosphatized wall (Fig. 130E,F) could reflect wall structure. Relatio n ships. A. sexalox could be compared with other h exasulcate sp ecies such as A. hexasulcatus (Missarzhevsky, 1974, p1.23, figs 6,7; Abaimova, 1978, figs 15,16,19�21,23-26; Val'kov,1982, pl.13, figs 1-16,21; 1987, pl.13, figs 17,18),A hariolus(Val'kov,1987, pl.13, figs 14-16), and A. isiticus (Missarzhevsky, 1974, p1.23, figs 11,12, Sokolov & Zhuravleva, 1983, pl.61, fig. 5). However, if the derivation of A. sexalox fromA. trymatus is accepted(see below) then its six-fold symmetry presumably would be convergent with these Soviet species, which stratigraphically appear older. Hexasulcate species described from China, including forms referred to A. cf. hexasulcatus (Jiang, 1980a, pl.1, figs 4,12; Luo et al., 1980, pt 1, fig.3), A. xishuiensis (Qian,1977, pl.1, fig.8; Yang et al.,1983, p1.1, fig.3) and possibly Anabaritellus sp. (Yin et al., 1980, pl.17, fig. 1 ) , differ in that none of the material appears to possess pits on the .steinkern grooves. General discussion Palaeobiology. Missarzhevsky (in Voronova & Missarzhevsky,1969) originally indicated A. trisulcatus to belong within the serpulid worms (Polychaeta), but even an assignment to the polychaetes was later regarded as doubtful by
197
Missarzhevsky (in Rozanov et al.,1969). Glaes sner (1976) continued to support serpulid affin ity, but omitted any mention of the distinctive triradial symmetry. Val'kov (1982) placed the anabaritids in a new Subclass(Angustimedusae) of the scyphozoan cnidarians. Fedonkin (1986) noted a possible relationship between anabar itids and a distinctive as�emblage of Ediacaran medusoids with triradial symmetry (Albumares, Tribrachidium) for which he erected the Class Trilobozoa (Fedonkin,1983). Fedonkin (1986) noted that even if trilobozoans are cnidarians, they are unlikely to be scyphozoans. Thus, while a cnidarian affinity remains conceivable for anabaritids (Missarzhevsky, 1974), absence of unequivocal data makes a place in the limbo of incertae sedis preferable. In this context, one should note that the three-fold structure on the proximal termination of the tube (Fig. 130M) indicates that this symmetry was established early in ontogeny, possibly even in the larval stage. Dzik's(1986) attempt to link Chancelloria and possibly other Cambrian forms(e.g.Pirania) to Anabarites requires no further attention. Should a cnidarian affinity receive further sup port, then a plausible arrangement of anabaritid soft parts could be devised, but in any event ac cretionar y g r owth implies a secretory epithe1ium (or pinacoderm). Prominent flanges in A. tricarinatus (Abaimova,1978) and appar ently Selindeochrea sp. (Val'kov,1982) indicate that epithelium could extend outwards for a con siderable distance. However, the exact mode of flange secretion is uncertain as they are thin and apparently lacked a central lacuna to house secretory tissue; perhaps such tissue lay over the leading edge of each flange. The internal keels must reflect infolding of the main epithelium, but to what extent other organ systems were ar ranged around a tri- or hexa-radial symmetry is speculative. Functional significance of the short extensions on the keels of some anabaritids, together with A. sexalox and A. trymatus, is not known, although a role in attachment seems con ceivable. A possible analogy lies with the tubes of scyphopolyps(Scyphozoa) in which the inner wall may bear tooth- like structures, albeit of obscure functional significance (Mierzejew ski,1986, p.141). Anabaritid ecology i s also sp eCUlative. Flanged species would be improbable members of a vagrant benthos; rather such structures might
Fig. 128. Anabarites sexalox Conway Morris & Bengtson, sp. nov. Horse GulJy, Parara Lst., UNEL1761 (A,B), UNEL1856 (C-L). A,B, SAMP30818, steinkern with prominent pits, x60. C,D, SAMP30819, steinkern. C, x60. D, x200. E,F, SAMP30820, partially preserved wall. E, x60. F, x90. G-I, SAMP30821, partially preserved wa1l. G,H, x90. I, x30. J- L, SAMP30822, steinkern. J, x60. K, detail showing initial development of sulcus (=internal keel), x200. L, pits on sulcus, x400.
198
STEFAN BENGTSON etal.
Fig. 129. Anabarites sexalox Conway Morris & Bengtson, sp. novo Horse Gully, Parara Lst., UNELl856 (A-E), 6429RSllO (F), UNELl853 (G-K), UNELl852 (L). A-E, holotype, SAMP30823. A, x60. B, x200. C, x150. D, x120. E, x60. F, SAMP30824, x60. G-K, SAMP30825, steinkern. G, x60. H, x30. I, x60. J, x90. K, x60. L, SAMP30826, steinkern, x50.
Fig. 130. Anabarites sexalox Conway Morris & Bengtson, sp. novo Mt. Scott Ra., Ajax Lst., UNELl873 (A- F), UNELl874 (G- T ) . A,B, SAMP30827, x90. C,D, SAMP30828. C, x60. D, x90. E,F, SAMP30829. E, x60. F, wall with possible ultrastructure, x600. G,H, SAMP30830. G, x120. H, x60. I,J, SAMP30831 . I, x60. J, x60. K, SAMP30832, x60. L-N, SAMP30833. L, x60. M, proximal end, x400. N, x90. O,P, SAMP30834, x90. Q, SAMP30835, x90. R, SAMP30836, x60. S,T, SAMP30837, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
199
200
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
have helped to confer stability.Even the asym metrically inclined annulations of A. sexalox (Figs 128G, 129A-F, 130A·.c,K, - L ,N,R, D,M,N) and at least some other taxa (e.g. Val'kov,1982, p1.10, figs I a,2a; p1.l4, fig.l) could have assisted in gripping sediment grains to prevent dislodgement. Phylogeny. Morphological transition betweenA. sexalox and A. t,ymatus could be achieved by sim p le accentuation of the secondary keels, al ready weakly expressed in A. t,ymatus (Fig. 127J,L), combined with a reduction in size. Both species possess peg-like extensions on the primary set of keels, and the external surface of A. t,ymatus may have been annulated. Such a shift in morphology is explicable by an alteration in timing of ontogenetic development entailing the peramorphicacceleration whereby the rate of development during ontogeny is increased so that ancestral adult stages occur in the juvenile descendant (McNamara, 1982). Stratigraphic relationship may support this suggestion, in that A. t,YlIUltus appears to precede A. sexalar:. Their co�occurrence in UNEL1852 and 1853 may in dicate a period of parent and daughter species co�existence. McNamara (1982,1987) stressed how peramorphic (and paedomorphie) descen dants arise as a result of ecological opportunities; even ifparent and daughter species co-occurthey occupy different parts of an environmental gradient. Co-occurrence of A. tryllUltus and A. sexalox might appear to contradict this proposi tion, but ecological separation (?water depth and sediment grain size) combined with reworking could provide an explanation. Other aspects of anabaritid evolution (Fig. 132) could be framed within the concept of peramorphoclines (McNamara, 1982, 1985, 1987). Thus the ancestral condition could be taken as a simple tube with a cross-section that increased in diameter during ontogeny, but remained circular. If they are related to the anabaritids, this could be expressed in Cambro tubulus, although their relative size suggests gigintism. It is worth noting also that a number of species of Hyolithellus, including H. isiticus (Missarzhevsky in Rozanovetal., 1969, p1.7. figs 1,17; Voronin eta l 1982,p l.5. figs 1,2; Sokolov & Zhuravleva, 1983, p1.60, figs 10,11; Hinz, 1987, p1.l4, fig.16) and H. insolitus (Voronin et al.,1982, p 1 . 5 , fig.5; Sokolov & Zhurav leva,1983,pI.60, figs 6a,b) are strikingly similar externally to some anabaritids, e.g. A. sewlox. .•
201
However, even though the transverse sections of Hyolithellus spp. are circular, their phosphatic composition may preclude an affinity with Anabarites. The triradial subdivision (Fig.132), perhaps heralded by the triangular cross-section of Tik sitheca, led t oAnabarites and similar forms (e.g., An gustiochrea and Mariochrea). Variations be tween the majority of .nominal species of Anabarites are largely a reflection of trivial dif ferences in keel development and longitudinal torsion of the tube, and may represent in traspecific variation. Further development of subdued furrows on the three main lobes oc curred in A. t,YlIUltUS, A. isiticus and species presently in Selindeochrea and Jakutiochrru, with a culmination in bexaradial symmetry being seen i nA. sexalox andA. hexasulcatus. The early growth stages inA. sexalox (Figs 1281, 129D,G I,K, 1 3 1E,G) show how this peramor hic form p recapitulates (Landing, 1988, p.690) the an cestral form of a tube that in cross-section develops from circular to trifoliate to subdued hexaradial to strongly hexaradial. Although this discussion refers to a single peramorphocline, there is no reason to reject iterative events. If A. sexalox arose from A. tlYlIUltUS a six-fold condition arose independent ofA. hexasulcatus ofthelowerTom motian (Mis sarzhevsky,1 974,1982). Direct evidence for evolutionary links between most anabaritid species is not yet available, but possibly Selin deochrea (S. tecta Val'kov,1982) could be derived from forms such as A. ternarius or A. tricarinalus, and these latter species could be traced from A. trisulcatus via A. tripartitus. The apparent facility of heterochronic change suggests recurrent parallel evolution, with hexasulcate forms appearing at least twice. Given gradations of hexaradial symmetry, separation of genera from Anabarites would seem to be arbitrary, and it is proposed that Anabaritellus(A hexasulcalus,A. xishuensis) be synonymized with Anabarites. Irrespective of whether anabaritid evolution involved one or more peramorphoclines, such heterochronic shifts could imply response to environmental gradients. In peramorphoclines of. Tertiary ir regular infaunal echinoids, McNamara (1985, 1987) linked the evolutionary series to invasion of p rogressively finer grained sediments. In anabaritids, smaller size and more closely spaced annulations of a hexasulcate end member (A. sexalox) of one peramorphocline could also rep-
Fig. 131. Anabaritessexa/oxConway Morris & Bengtson, sp. novo Mt. Scott Ra., Ajax Lsl., UNEL1874. A,B, SAMP30838, x90. C,D, SAMP30839. C, )1.65. D, )(90. E-H, SAMP30840, stein kern. E, )(60. F, apertural view, )1.200. G, )(90. H, pl)s�ible sbell ultrastructu re, x400. I, SAMP30841, internal wall, x90. J,K, SAMP30842, intern al w all, )1.90. L, SAMP30843, inlernal wall, )(90. M,N, SAMP30844. M, i nternal wan and annulations, )1.60. N, anoolation, x900.
202
STEPAN BENGTSON
et al.
Time
Taxa
0
0
0
[)
0
0
0
[)
0
0
0
0
0
0
0
0 0
A. tristlchus; A. trymatus; A. gracilis
A. trlsulcatus A. trlpartltus
Q
0
0
A. hexasulcatus A. sexalox A. isltlcus Sellndeochrea tecta
'\�t,.
CV
g;.
Cambrotubulus
Ontogeny
Fig. 132. Anabaritid phylogeny based on the concept of derivation along a peramorphocline. resent adaptation to substrate. If the functional significance of the longitudinal keels could be solved, this too might help to explain the adapta tional significance of the peramorphocline.
Stratigraphic utility.
Siberian and Kazakhstani anabaritids are either from the lower Tommotian or the Manykay (and Nemakit-Daldyn) horizon, which is ostensibly slightly older (e.g., Mis sarzhevsky, 1982). Chinese occurrences (Con way Morris & Chen, 1989) in the Meishucunian are widely claimed to be equivalent to the Tom motian and/or Nemakit-Daldyn. The Australian species, from strata of Atdabanian age yielding trilobites, shows that the group is long-ranging, and their use in correlation and zonation requires caution. If the striking similarity between A. trymatus andA. tristichus (andA. sexaloxandA. hexasulcatus) reflects common descent, their biostratigraphic utility may be limited, but con vergence in form is plausible. High ranging anabaritids in the Lower Cambrian of eastern
Newfoundland (Landing,1988) are not notably similar to the Australian forms.
DECOLLATING TUBULAR FOSSILS [SB] The Parara Lst.lJ.bounds with truncated segments of calcareous tubes in phosphatic residues from Horse Gully; they are found also in the Parara at Curramulka and Kulpara, as well as in the Onlparinna Shale at Bunyeroo Gorge. Similar fossils have various names in the Chinese litera ture (Qian,1977; Anon., 1979; Xiao & Zhou, 1984; Xing et al.,1984; Duan, 1 984), and they have been interpreted as hyoliths with discoidal protoconchs. The first name applied to these fossils was 'Paragloborilus mirus (He) (MS)' (Qian,1977; see Qian & Bengtson,1989, concerning author ship). Subsequently it was made the type species
EARLY CAMBRIAN FOSSILS, S. AUST.
o f Actinotheca X i a o & Z h o u , 1 9 8 4 , a n d Emeitheca Duan,1984, the former name having priority. The Australian m aterial demonstrates that the characteristic terminations of Actinotheca tubes are not initial growth stages, but are formed secondarily, by sealing the living chamber with a septum-like partition and subsequent decolla tion of the earlier formed shell. A clear analogue to Actinotheca's mode of conch formation exists in the Recent Caecum (Fretter & Graham,1978), a little prosobranch living on sandy or muddy bottoms. Only the protoconch is coiled, and the slightly curved conch repeatedly loses its earlier formed parts, with a secondary convex wall forming a seal. A few other Recent gastropods, for example the freshwater Thiaridae, have a similar habit of decollation. Although Actinotheca has been grouped with hyoliths, little evidence supports this interpreta tion. No definite opercula have been identified, and if the occasionally associated simple disks belong to Actinotheca, they do not show any features characteristic of hyolith opercula. Caecum has an unmineralized operculum, but there is no clear evidence to suggest homology with these disks. Structures associated with the zone of decol lation (see description of A. holocyclata) are distinctlve. A comparative study of decollation mechanisms in Recent gastropods may be useful in interpreting their functional morphology in Actinotheca, and perhaps also in assessing af finities, which remain open.
Phylum, class, and order uncertain Family CUPITHECIDAE Duan,1984 * 1984 Cupithecidae Duan, p.154. *1984 Emeithecidae Duan. p.158.
Actinotheca Xiao & Zhou, 1984 1984
Actinotheca Xiao & Zhou, p.146.
*1984b Cupittheca Duan (MS) in Xing et al., p.152 *1984 Cupitheca Duan, p.154. *1984 Arcitheca Duan, p.155. *1984 Varitheca Duan, p.156. ·1984 Ensitheca Dnan, p.157. ·1984 Emeitheca Dnan, p.158.
(Priority is allocated according to title page dates: Xiao & Zhou, 1984, was published in January, Xing et ai, 1984b, in February, and Duan, 1984 [date according to article biblid 1983], in October.)
203
Type species. Paragloborilus mirus He in Qian,
1977. Other species. (list not annotated for synony mies) A. brevituba (Duan,1984); A. coarctata (Du an, 1984); A. costellata Xiao & Zhou,1984; A. dolioformis Xiao & Zhou,1984; A. ensiformis (Duan,1984); A. gracilis (Duan,1984); A. hemicyclata sp. nov.; A. holocyclata sp. nov.; A. intermedia (Duan,1984); A. mammilata (Duan, 1984);A. manicae (Duan,1984);A.? ovaliformis Mam b etov i n Mi ssarzh e v s k y & Mam betov,1981; A. clathrata sp. nov.; A. semigyra (Duan,1984);A. suborbicularis (Duan, 1984). Distribution. China, Australia, Kazakhstan 1;
Lower Cambrian. Diagnosis. Conch straight or curved, with cir
cular to oval cross-section, low angle of diver gence. Older parts of conch successively aborted during ontogeny in connexion with formation of secondary transverse wall sealingoffapical end. Operculum, if present, a simple disc. Remarks. Through the courtesy of Dr Qian Vi,
Nanjing, we have been able to investigate three topotype steinkems of Actinotheca mira (Fig. 133). The characteristic termination is identical to steinkems of Australian species, confirming generic identity. Australian species, however, cannot be readily distinguished in steinkems, which makes it dif ficult to verify reports of A. mira outside its type area. Topotypes of A. mira are somewhat flat tened in transverse cross section (Fig. 133B, E,G), and thereby resemble A. hemicyclata sp. nov., but specific identity cannot be proven given the state of the type material ofA. mira. Duan (1984) differentiated the Cupithecidae and Emeithecidae, with 5 genera, and 10 species from the Xihaoping Formation of the Shen nongjia District, Hubei, China. The character taken to differentiate the two families is depth of incision around the convex terminal wall. Duan's specimens may be secondarily coated steinkems, however, as his schematic drawings(Duan,1984, fig.6) show walls of equal thickness across the j unction between cylindrical and convex wall, whereas the Australian specimens demonstrate a more complex structure in this region. As seenfrom AustralianActinotheca (Figs 134,136), the depth of the incision on the internal moulds is highly variable even within single popula tions.There seems to be no basis to employ this character to distinguish the two families.
204
STEFAN BENGTSON et al.
Fig. 133. Actinotheca mira (He, 1977), stein kerns. Maidiping, Sichuan, China (per Qian Yi, Nanjing). All x35, except H. A,B, SMNHX3253. C-E, SMNHX3254. F-H, SMNHX3255. H,-detail of base with secondary wall, x175.
Duan's generic distinctions appear to be based on 1, preservation (presence or absence of faint growth lines may depend on whether or not any shell matter is preserved on moulds), 2, contrasts between functional conchs and discarded seg ments (e.g., Ensitheca represents complete living chambers, the other genera aborted segments), and 3, excessive splitting of variable forms. Con sequently Duan's (1984) genera are regarded as junior synonyms ofActinotheca. Whether any of the ten species are recognizable as separate taxa cannot be judged from available information.
Actinotheca'holocyclata Bengtson, sp. novo (Figs 134-136) Etymology, Greek holos, complete, and kyklos, circle, referring to the complete annulations on the surface of the tubes, an adjective. Material, Holotype SAMP30845 (Fig. 134A-E) from UNEL1856 (Horse Gully, Parara Lst., basal 1m); C. 60 paratypes. Distribution. H o r s e G u l l y , P a r a r a L s t . (UNEL1 856, 6429RS 106-109, UNEL1854, 6429RSl13(?); Kulpara (6529RS105). Diagnosis, Densely set annulations, 20-30f.Lm apart, and circular to almost circular transverse cross-section. Description. The species is commonly repre sented by short, cylindrical tube sections, seldom more than twice as long as the maximum diameter (but see Figs 1341, 136A). The cross section is circular (Fig. 134E) to oval. Diameter _
is 0.2-0.7mm, and angle of divergence is low. Conchs are straight to curved. In acid residues the species usually occurs as phosphatized steinkerns (Fig. 135), and thin sec tions confirm preferential phosphatization of in filling matrix (Fig. 136C,E-H); the shell wall itself consists of sparry calcite. In the Horse Gully section phosphatization has commonly penetrated deeply the exterior shell wall, with preference for replacement to occur along tubules (Figs 134F-L,N,O, 136G). The outer surface is covered with regular, slightly sinuous, annular ridges, C. 20-30 fLm apart (Fig. 134). Ridge profile varies, but is usually steeper toward the apical part of the conch (Figs 134C, 136H). Inter-ridge areas are usually delimited, flat to concave, with about the same width as the ridges (Fig. -134C). The an nular ridges are not reflected internally, so steinkerns are smooth (Figs 135A, 136B,G). Each conch is sealed off apically by a septum like transverse wall (Fig. 136G) which is convex apically and about the same thickness as (or slightly thinner than) the cylindrical wall. The boundary between convex and cylindrical wall is marked by a deep circular groove, less pronounced on the inner than outer side. This difference is due to thickening of the peripheral part of the convex wall and to a circumferential flange formed by the outer part of the cylindrical wall (Figs 134I, H,L, 136). The outer rim of the convex wall has a distinctly flat cylindrical sur face (Fig 134H,O) opposite the apical projection of the inner surface of the cylindrical wall (Figs 134H,L, 136). The apical termination of the conchs is thus defined by a septum, behind which earlier sec tions were autotomized along a transverse line of
EARLY CAMBRIAN FOSSILS, S. AUST.
205
Fig. 134. Actinotheca holocyclata Bengtson, sp. novo Horse Gully, Parara Lst., UNEL1856 (A-O), and 6429RS109 (P). All x50 except where otherwise indicated. A-E, holotype, SAMP30845. C, x500, detail, position indicated in B. D, x500, detail of junction beween cyl indrical and convex wall. F-H, SAMP30846. H, x500, detail of G. J, SAMP30847. J, SAMP30848. K,L, SAMP30849. L, x500, detail of K. M, SAMP30850. N,O, SAMP30851. 0, x250, detail of N. P, SAMP30852.
206
STEFAN BENGTSON e t al.
Fig. 135. Actinotheca holocyclata Bengtson, sp. nov., steinkerns. Horse Gully, Parara Lst., UNEL1856. A-C, SAMP30853. A,B, x35. C, x500, detail, position indicated in B. D,E, SAMP30854. D, x35. E xlOOO, detail, position indicated in D.
weakness, which may cut obliquely across the annular ridges (Fig. 134A,B,G,M-P). No conch has been found with more than one such septum. On the other hand, many of the short segments show evidence of having been in their turn dis carded: they have a smooth apertural edge that also obliquely cuts the annular ridges (Fig. 134B,P). In thin section (Fig. 137) one specimen shows what superficially appears to be a septum within the conch. This unique feature may be inter preted as an adventitious septum formed when the secretory epithelium became detached from the convex wall before it had attained full thick ness. This interpretation is supported by the relative thicknesses of the convex and cylindri cal walls. In normal specimens (Fig. 136) the thickness of the convex wall is generally 70100% of the cylindrical wall, but may be as low as 40% (Fig. 136B). In the specimen with the adventitious septum (Fig. 137), the correspond ing ratio is only about 30%, suggesting that the
'septum' is really a detached part of the convex wall. Earliest skeletal ontogeny is not known, and convex wall terminating the smallest observed segment has a diameter of 0.2 mm. The rim o f the convex wall has a transverse system often preserved as phosphatized rods, that apparently represent tubules. In specimens from acid residues they have a thickness of 3-5 f.1m (Fig. 134H,L,0), whereas in thin sections less phosphatized specimens have rods c. 1-3 f.1m thick (Fig. 136G,H). Pronounced in the outer part of the wall they taper inwardly and usually terminate before the inner surface (Figs 134H,0, 136G,H). The outer surface of the cylindrical rim of the convex wall has a corresponding dense pitting (Fig. 134D,0), whereas the inner surface is smooth (Figs 134H,0, 135C). Rods are also present in the cylindrical wall, but are somewhat coarser than those described above: 5-1Of.1m in the strongly phosphatized specimens (Figs 134H, 135E), but 2-5f.1m in
EARLY CAMB R I AN FOSSILS, S. AUST.
207
Fig. 136. Actinotheca holocyclata Bengtson, sp. novo Horse Gu lly, Parara Lst., U NEL1856. Thin sections in plane p olarized light. A-F, x50. G,H, x250.A,SAMP30855.B, SAMP30856. C, SAMP30857. D, SAMP30858.
E, SAMP30859. F,G, SAMP30860. G, detail of F. H, SAMP30861 (left) and SAMP30862 (right).
lightly phosphatized material (Fig. 136G). They may follow the course of the surficial annulations (Fig. BSC) but sometimes are more irregularly arranged (Fig. 1341). They show no evidence of tapering, and appear to traverse the entire shell wall. No opercula have been observed occupying the conch aperture. Figure 138 shows an assemblage of simple concavo-convex circular discs from o n e of the s a mples rich in conchs of A. holocyclata. They lack the steep sides that would identify them as detached convex walls of the apical end of the conch. The concave side has a
circular ridge inside the periphery (Fig. 138A,B), which may have served to stabilize an operculum against the apertural rim of the conch. These discs are tentatively interpreted as opercula of Actinotheca, but further evidence is necessary to establish their nature beyond doubt. Biology. Successive discarding of segments during ontogeny is probably a generic feature. The reasons for this interpretation, as against separation post mortem along lines of weakness associated with internal septa, are:
208
STEFAN BENGTSON et al.
Fig. 137. Actinotheca sp., thin section of specimen with false internal sep tum. Horse Gully, Parara Lst., UNEL1761. SAMP30863. A, x50. B, x250.
1, the convex walls do not occur as internal septa; 2, intersection between cylindrical and convex walls is always clean. If this line was so weak after death, it is difficult to see what would have prevented dismemberment during life. The im perforate convex wall (except for the margi nal parts abutting the cylindrical wall) shows that living tissue must have been confined to the chamber in front of the wall and thus segments could not have been held together by living tissue; 3, the partition line must have been f ormed secondarily as it conforms to the suture with the convex wall rather than the annu lae that repre sent growth lines. It is thus difficult to interpret as a passive line of weakness, especially as there is no reason why the formation of a septum should weaken the conch. 4, concentration of tubules peripherally in the convex wall (Fig. 136H), abutting the cylindrical wall, together with their absence in other parts of the convex wall, suggests that the tubules had an active f unction in autotomy. Most likely, per haps, they acted as conduits for releasing shell dissolving substances to the zone of separation when the sealing wall had been formed. The
tubules often did not reach the inner surface of the wall, indicating that after separation the con vex wall was thickened by the mantle. Such a 2-stage formation of the convex wall is a lso suggested by the adventitious septum (Fig. 137) discussed above. The explanation f avoured in the Chinese literature, that the convex wall represents the initial part of the conch, is rendered f urther un likely by 1, wide variation in diameter of the convex wall, and 2, evidence of discards. The proposed decollation sequence is shown in Fig. 139. This mode of growth is probably related to the low angle of divergence of the conch. By periodically discarding older parts, the conch would avoid extreme length with increasing body size, a factor that might hamper inferred mobility. Decollation may thus be seen as an alternative to coiling. Thus the living chamber probably corresponds to at least the length of conch seen in Fig. 136A . The numerous short segments mostly represent discards. Taken in isolation they give a f alse impression of the shape of the living animal.
.
EARLY CAMBRIAN FOSSILS, S. AUST.
209
Fig. 138. Operculum-like objects co-occurring with conchsofActinotheca holocyclata Bengtson, sp. novo Horse Gully, Parara Lst., UNEL1854. All x 100. A,B, SAMP30991. C,D, SAMP30992. E,F, SAMP30993. G, SAMP30994.
210
STEFANBENGTSON etal.
Fig. 139,' Actinotheca sp. Diagram to show proposed decollation event in longitudinal section. Shell - black, soft parts - grey (suggestion of tentacle crown entirely hypothetical). A, animal occupying whole tube. B, soft parts withdrawn from closed end. C, new convex wall formed inside tube. D, old section of tube released by dissolution of shell. E, old section discarded and new convex wall further thickened internally.
Actinotheca hemicyclata Bengtson, sp. novo (Fig.140)
Etymology. Greek hemi-, half, and kyklos, circle ; referring to the half rings formed by the incom plete annulations on the surface ofthe conchs, an adjective. Material. Holotype SAMP30864 (Fig. 140A-F) from UNEL1856, Horse Gully, Parara Lst.; C. 10 paratypes. Distribution. H o r s e (UNEL1856, 1854).
Gully,
P arara
Lst.
Diagnosis. Ovoid transverse cross-section and wrinkle-like annulations on one of the broad sides, other side smooth. Descri ption. The conchs of this species are somewhat flattened, the transverse cross-section is ovoid, with a length:width ratio of 1.2-1.3:1. There is a tendency to 'dorsoventrality' in that one of the broad sides, arbitrarily' dorsal', carries a set of irregular wrinkle-like annulations, more coarsely set than inA. holocydata. The 'ventral'
side is smooth and usually somewhat less convex than the dorsal one. The junction between cylindrical and convex walls is indistinguishable from A. holocydata, and tubular structures also open to the outside (Fig. 140F). The convex wall may show indis tinct concentric structures (Fig. 140E) that could reflect stepwise mineralization of the wall.
Comparisons. This form occurs with A. holocy data but is easily distinguished on the basis of the characters mentioned above. There appear to be no intermediate forms. As remarked above, the type species ofActinotheca, A. mira, also has a somewhat flattened transverse cross-section, but absence of information on its external sculp ture prevents discussion of possible synonymy withA. hemicydata. Actinotheca c1athrata Bengtson, sp. novo (Figs 141, 142)
Etymology. Latin adjective dathratus, latticed, referring to the surface sculpture. Material. Holotype SAMP30866 (Fig.l41D,E),
EARLY CAMBRIAN FOSSILS, S. AUST.
211
Fig. 140. Actinotheca hemicyclata Bengtson, sp. nov., discarded section, holotype, SAMP30864, Horse Gully, Parara Lst., UNEL1856. All x50, except E and F. E, detail of C, x175. F, detail of junction between cylindrical and convex waIls, xlOOO.
from UNEL1852, Horse Gully, Parara Lst.; c. 30 paratypes. Distribution. Horse Gully, Parara Lst. (UNEL 1852, 1853, 6429RSl13). Diagnosis. Reticulated surface pattern formed by densely spaced annulations (2 0-30f.Lm apart) and longitudinal ridges. Transverse cross-sec tion circular to subcircular. Description. Similar to A. holocyclata and with circular to subcircular transverse cross-section. The surface is finely annulated (c. 20-30f.Lm apart) and bears longitudinal ridges. In combi nation, these produce a reticulated ornament (Figs 141C, 142D). Structures connected with the convex wall are identical to those in the other species described herein. Discarded segments are 1-2 times longer than wide, and often recognizable on account of their smooth adapertural rim obliquely cutting the transverse annulations (Fig. 141A,B). Other
specimens (Fig. 142) are longer and appear to represent living chambers; however, the convex wall is not preserved. Comparisons. Internal moulds of A. clathrata and A. holocyclata are indistinguishable, but the surface sculpture of the former is diagnostic. Furthermore, except for a possible specimen of A. holocyclata in 6429RSl13, there is n o stratigraphic overlap ofthe two species a t Horse Gully, so that A. clathrata appears to replace A. holocyclata at the 19m level in the Parara Lst. T h e s p e c i e s o c c u r r i n g at Ku l p a r a is A. holocyclata; the specimens of Actinotheca from the Mt. Scott Ra. are not well enough preserved to permit identification to species.
HYOLITHS [SB] These etched hyoliths are secondarily phospha tized shells. Many hyolith conchs, including those few described from the Lower Cambrian
212
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
213
Fig. 142. Actinotheca clathrata Bengtson, sp. nov., probable living chambers. Horse Gully, Parara Lst." ' 6429RS1l3. All x50, except D. A,B, SAMP30871. C,D, SAMP30872. D, detail of C, x500. of South Australia (Tate, 1892), are of centimeter rather than millimeter size; o u r sampling methods favoured small and juvenile forms. Hyolith taxonomy remains in a state of flux, particularly in the Lower Cambrian where many genera and species have been erected for imper fectly preserved and inadequately described material. As a full taxonomic revision of all such taxa is an almost insurmountable task, the poorly founded unrevised names may be best left to wither in oblivion rather than become entrenched on the basis of insecure comparisons. Marek (1967, p.66) stressed that hyolith taxa should not be erected without detailed information on both conch and operculum morphology, a rule effec tively i gnored in the taxonomy of Lower Cambrian hyoliths. For Australian taxa, we ad here to Marek's advice for Parkula and Hyp tiotheca. For two new species of Microcornus the opercula have not been identified with cer tainty, but the conch morphology is sufficiently distinctive to make them useful for regional biostratigrap hy.
Phylum incertae sedis Class HYOLITHA Marek,1963 Order ORTHOTHECIDA Marek,1966 Family CIRCOTHECIDAE Missarzhevsky, 1969
Conotheca Missarzhevsky,1969 *1969 Conotheca Missarzhevsky in Rozanov et al., p.112. . *1981 Simplotubus Singh & Shukla, p .163.
Type species. Conotheca mammilata Missar zhevsky, 1969. Distribution. Siberian Platform, Kazakhstan, China, India, Australia; Lower Cambrian. Diagnosis. Conchs with circular cross-section and straight aperture; surface sculpture of weak growth lines; apical part slightly bulbous. Oper culum with cardinal processes and clavicle-like tubules.
Fig. 141. Actinotheca clathrata Bengtson, sp. nov., discarded sections. Horse Gully, Parara Lst., UNEL1852. All x50 except where otherwise indicated. A-C, SAMP30865. B, oblique view of 'aperture', x 100. C, detail of A, x 250. D,E, holotype, SAMP30866. F-H, SAMP30867. I-K, SAMP30868. L-M, SAMP30869. N,O, SAMP30870. 0, detail of N, x500.
214
STEFAN BENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
215
Fig. 144. Conotheca australiensis, Bengtson, sp. nov., opercula. Curramulka, Parara Lst., UNEL1849. All x60. A and C, stereo-pairs. A-E, holotype, SAMP30877. A, inner view. B, oblique lateral view. C, outer view. D, oblique dorsal- outer view. E, oblique dorsal - inner view. F-I, SAMP30878. F, inner view. G, outer view. H oblique lateral view. I, oblique dorsal- inner view. J,K, SAMP30879. J, outer view. K, oblique dorsal- outer view. L,M, SAMP30880. L, inner view. M, oblique lateral view. N, oblique dorsal- inner view.
Fig. 143. Conolheca auslraliensis, Bengtson, sp. nov., conchs. Curramulka, Parara Lst., UNEL1849. All x30, except where otherwise stated. A-D, SAMP30873. D, detail of C, x300. E-G, SAMP30874. G, detail of F, x300. H-K, SAMP30875. J, detail of I, x150. K, detail of J, xlOOO. L-N, SAMP30876. N, detail of M, x600.
216
STEFAN BENGTSON et al.
Conotheca australiensis Bengtson, sp. nov. (Figs 143,144)
Etymology. Latin australiensis, from Australia. Material. Holotype SAMP30877 (Fig. 144A-E) an operculum, from UNEL1849, Curramulka, Parara Lst.; paratypes 11 conchs and 7 opercula. Distribution. Curramulka, Parara Lst. (UNEL 1845?, 1848, 1849, 1851). Diagnosis. Operculum with cardinal processes about 1/5 as long as the opercular diameter, and about six pairs of clavicle-like tubules. Description. Conchs are up to c. 3mm long, somewhat recurved, and with a circular to oval cross-section. The initial part is bulbous (Fig. 143G). The angle of divergence is initially only a few degrees, increasing to c. 20° closer to the aperture. The apertural plane is perpendicular to the long axis of the conch. The margin is rounded a n d s o m e w ha t bevelled f r o m t h e inside (Fig.143D). One specimen (Fig. 143H- K) has a blunt termination, suggesting breakage along an . internal septum. (Because there are larger com plete specimens known (Fig. 143A- D), the blunt termination is most likely not decollation com parable to Actinotheca.) The conch surface is almost smooth, except for fine, densely set growth lines parallel to the aperture (Fig. 143A,L). Opercula are circular to slightly oval in profile. The outer side is gently convex and smooth, except for faint, concentric growth lines. The growth center is situated about 1/3 of the diameter from the dorsal edge. The inner side is a distinctly offset marginal zone with a width of about 1/10 of the diameter. The cardinal proces ses are straight, diverge at c. 30-45°, and may be as long as 1/5 of opercular diameter (Fig. 144B). They are closely set inside the marginal zone. Laterally on the central portion are six pairs of clavicle-like tubules diverging from the center of growth (Fig. 144A,F,L). Conchs and opercula have not been found ar ticulated. They are placed in one species because 1, they co-occur, 2, match in size and profile, 3, have identical surface structure and preservation, and 4, lack associated conchs or opercula with which they could be matched. Comparisons. Comparisons with other species of Conotheca are difficult, because no other oper cula have been described, and insufficient infor m a t i o n is a v a i l a b le on morpholog y a n d variability of conchs. The conch of C. australi ensis appears similar to that of the Tommotian
type species, C. mammilata, although Missar zhevsky (in Rozanov et al.,1969) found no evidence of septa in the type series. C. mammi lata from the Atdabanian of eastern Massachu setts (Landing,1988, fig.9:10-12,17) conform to the same conch morphology. The Atdabanian C. circumflexa M issarzh evsky in Rozanov et al.,1969, has a slight helical growth component to the conch. Other species (C. corniformis Mambetov in Missarzhevsky & Mambetov, 1981; C. curta Missarzhevsky, 1981; C. dahai ensis Jiang in Luo et al., 1982; C. shennong jiaensis Duan,1984) are inadequately preserved and illustrated. A number of Lower Cambrian species referred to Circotheca Sysoev,1958, may also be related to these forms, although the type species, the Middle Cambrian Circotheca stylus (Holm,1893), differs considerably in shell form and sculpture from Conotheca. Missarzhevsky (in Rozanov et al.,1969) ex pressed doubts as to the hyolith nature of Con otheca. If the identification of the Australian conchs and their opercula is correct, such doubts may be allayed.
Order HYOLITHIDA Matthew, 1899 Family unassigned Microcornus Mambetov,1972 1972 Microcornus Mambetov, p.140. 1974b Nelegerocornus Meshkova [nomen nudum], p.54.
Type species. Microcornus parvulus Mambe tov,1972 Other species. Microcornus? anhuiensis Xiao & Zhou,1984; M. attenuatus (Meshkova, 1974b); M. elongatus Missarzhevsky,1981; M. eximius Duan,1984; M. marginatus (Meshkova,1974b); M. petilus sp. nov.; M. pinyuis Duan,1984 (?=M. eximius); M. simus Missarzhevsky,1974; M. talasicus Mambetov,1975. Diagnosis. Shell small, dorsal side with pro nounced median ridge a nd flattened flanks, ventral side weakly convex, transverse cross sec tion rounded triangular. Dorsal apertural edge straight or with slight median sinus, ligula semi circular. Initial part bulbous, delimited from adult part by constriction, and usually recurved towards dorsal side. Surface sculpture fine wrinkles parallel to apertural margin. Operculum with narrow cardinal shield. Distribution. Atdabanian to Botomian, Kazakh stan, Mongolia, China, Australia, England.
EARLY CAMBRIAN FOSSILS, S. AUST.
217
Fig. 145. Microcornus petilus Bengtson, sp. nov., conchs. SAMP30881. Curramulka, Parara Lst., UNEL1763b. A, dorsal view, x50. B, lateral view, x50. C, detail of B, x500.
Remarks. M icrocornus was established on small specimens with bulbous protoconch and semicir cular ligula, and operculum preserved in posi tion. Many species attributed to Microcornus are probably small adults a few millimeters in . length, but juveniles of larger hyolithids may also approach the shape of Microcornus. M e sh kova (1 9 7 4 b ) a t t e m p t e d to e r e c t Nelegerocornus based 0 n conchs 0 f three species from the the late Atdabanian to early Botomian of the Siberian Platform. The declared type species, N. revolutus, was not described or diag nosed, and although figured (Meshkova, 1974b, p1.9, fig.8) is a nomen nudum (ICZN, article 13).
The figure resembles Microcornus. No mag nification was given, but Meshkova stated the maximum length of Nelegerocornus conchs to be 5mm. The specimen figured (and described) as N. attenuatus (Meshkova, 1974b, p1.9, fig.4) appears to be a broken specimen of 'N. revolutus' from the same beds. The one figured as N. mar ginatus is incomplete, but has a general form and lateral growth lines similar to M. elongatus and M. eximius Duan,1984.
Microcornus petilus Bengtson, sp. novo (Figs 145-147)
218
STEFANBENGTSON e tal.
Fig. 146. Microcornus petilusBengtson, sp. nov., conchs. Horse Gully, Parara Lst. All x50, except G. D and K stereo-pairs. A-C, SAMP30882 from 6429RSllO. A, dorsal view. B, dorsolateral view. C, oblique apertural view. D-G, SAMP30883 from UNEL1856. D, dorsal view. E, dorsolateral view. F, oblique apertural view. G, detail of E, x500. H-J, SAMP30884 from UNEL1856. H, dorsal view. J, dorsolateral view. J, oblique apertural view. K,L, SAMP30885 from UNEL 1856. K, dorsal view. L, lateral view. M,N, SAMP30886 from UNELl856. M, dorsal view. N, lateral view.
EARLY CAMBRIAN FOSSILS, S. AUST.
219
Fig. 147. Microcornuspetilus Bengtson, s p. nov., conchs. Horse Gully, Parara Lst., U NEL1856. All x50, except where otherwise stated. A and F stereo-pairs. A-E, holotype, SAMP30887. A, dorsal view. B, dorsolateral view� C, detail of B, x500. D, detail of B, x200. E, oblique apertural view. F H, SAMP30888. F, dorsal view. G, lateral view. H, oblique apertural view. -
Etymology. Latin petilus, thin, slender; referring
to conch shape.
a conch, from UNEL1856, Horse Gully, Parara Lst.; c. 50 paratypes.
Material. Holotype SAMP30887 (Fig. 147A-E)
Distribution. Horse Gully, Parara Lst. (UNEL
220
STEFAN BENGTSON et al.
Fig. 148. Microcornus eximius Duan, 1984, c onchs. Horse Gully, Parara Lst. All x50, except D. A-D, holotype, SAMP30889 from 6429RS11 O. A, dorsal view. B, dorsolateral view. C, oblique apertural view. D , detail of B, x150. E-G, SAMP30890 from 6429RSI09. E, dorsal view. F, dorsolateral view. G, oblique apertural view. H-J, SAMP30891 from UNEL1856. H, dorsal view. I, lateral view. J, oblique apertural view.
1852, 1854, 1856, 6429RSllO); Curramulka, Parara Lst. (UNE L1845, 1846,1848,1849); Mt Scott Ra.,Ajax Lst. (UNEL1866, 1869?, 1871?, 1872-1874).
Diagnosis. Slender conchs (15-20° divergence
angle) with dorsal median ridge and sinus. Ten dency towards development of lateral lon gitudinal ridges on the dorsal side, associated
EARLY CAMBRIAN FOSSILS, S. AUST.
221
Fig. 149. Parkula bounites Ben gtson, gen. et sp. nov., conchs. Kulpara, Parara Lst., 6529RS10 5. All x80. A-C, holotype, SAMP30892. A, dorsal view. B, dorsolateral view. C, oblique apertural view. D-F, SAMP30893. D, dorsolateral view. E, dorsal view. F, oblique apertural view.
with a breaking up of transverse sculptural ele ments. Operculum unknown. Description . Conchs are slender (divergence angle c. 15-20°), and normally less than 2 mm long; the longest specimen (Fig. 145) is almost 3mm, but aperturally incomplete. The transverse cross-section is rounded triangular. There is usually a curvature towards the dorsal side (Figs 146B,L, 147B,G), but straighter specimens occur (Fig. 146E,I), and in some specimens a characteristic kink may be developed near the apical end (Figs 145B, 146N). Dorsally the aper tural edge has a slight median re-entrant (Fig. 147 A). The ligula is semicircular in outline (Figs 146A, 147A,F). The dorsal surface has a weak median ridge (Figs 146D,F, 147A,E). Lateral ridges may also be visible, mostly expressed in the course of the transverse elements of the surface sculpture: these form short segments, curved toward the aperture, their zone of junction marking the lon gitudinal ridges (Fig. 145). Often, however, ad jacent segments overlap so that no distinct longitudinal l ines develop (Fig. 1 47C). The ventral surface has distinct transverse sculpture
parallelling the outline of the ligula (Figs 146L, 147G). The protoconch is variable in shape, but generally bulbous and separated from the mature conch by a slight constriction, 200-400 f.1m from the apex. Faint growth lines may appear before the constriction (Figs 146E,J,L, 147B,D). There is usually a pointed apex (Figs 146L, 147D). Taxonomic comparisons. The species appears to be most similar to M. elongatus, but differs in its more elongate shape and more complex surface sculpture. It differs fromM. eximius in the same features, and also in having a more convex ventral side.
Microcornus eximius Duan,1984 (Fig. 148) ?1975 Microcornus cf.parvulus Mambetov; Mat thews & Missarzhevsky, p.297, p1.2, fig.2. *1984 Microcornus eximius Duan, p.153, pl.1, fig.5. ?*1984 Microcornuspinyuis Duan, p.153, pl.1, fig.lO. ?l987 Microcornus cf. parvulus Mambetov; Hinz, p. 68, p1.14, figs 22,23.
222
STEFAN BENGTSON et al.
Fig. 150. Parkula bounites Bengtson, gen. et sp. nov., opercula. Kulpara, Parara Lst., 6529RSI05. All x80. A and E stereo-pairs. A-D, SAMP30894. A, dorsal view. B, anterior view. C, posterodorsal view. D, oblique lateral view. E-H, SAMP30895. E, dorsal view. F, anterior view. G, posterodorsal view. H, oblique lateral view.
Material. C. 40 specimens. Distribution. Horse Gully, Parara Lst. (UNEL 1852, 1853, 1856, 6429RS106, 6429RS109, 6429RSllO, 6429RS1l2).
Diagnosis. Conchs with 25-30° divergence angle and a dorsal median sinus. Transverse ar ched sculptural elements on dorsal side unbroken laterally. Operculum unknown.
EARLY C AMBRIAN FOSSILS, S. AUST.
223
Fig. 151. Parkula bounites Bengtson, gen. et sp. nov., operculum, SAMP30896, Kulpara, Parara Lst., 6529RS105. All x80. A, stereo-pair, inner view. B, posterior view. C, lateral view.
Description. Conchs have an angle of divergence c. 25-30° and are up to 1.6mm long. There is little or no dorsoventral curvature. The transverse cross-section is rounded triangular, with an al most flat ventral side. The dorsal apertural edge has a median re-entrant (Fig. 148H). The ligula is semicircular. Dorsal ornamentation consists of fine trans verse (growth) lines that join in a Vat the midline and form aperturally convex curves laterally. On the ventral side the lines follow the outline of the ligula (Fig. 1481). The bulbous protoconch is isolated by a constric tion c. 200-250f.1m from the pointed apex. Faint growth lines may be visible on the protoconch near the constriction (Fig. 148D).
Comparisons. Di ffers from M. pa rvulus i n having a median sinus a t the dorsal apertural edge. This sinus, however, appears to be present in the otherwise similar M . cf. parvulus from Comley, Shropshire (Hinz,1987). Preservation of the Comley specimens is too poor to allow a
definite identification. Comparison with M. petilus is under that species above. Parkula Bengtson, gen. nov.
Etymology. Aleutian parka, hooded garment, and Latin dimi'lutive suffix -ula, alluding to the convexity of the operculum. The name is also an anagram of Kulpara, near the type locality Type and only species. Parkula bounites sp. novo Diagnosis. Straight conchs with lenticular cross section, faint dorsal median ridge, and semi-el liptical ligula. Surface sculpture of transverse striations and irregular longitudinal wrinkles. Opercula with strongly convex conical shield, short cardinal processes, and one pair of short clavicles ending in blade-like projections. Parkula bounites Bengtson, sp. novo (Figs 149-151)
Etymology. Greek bounites, dweller in the hills;
224
STEFAN BENGTSON et al.
Fig. 152. Hyptiotheca karraculum Bengtson, gen. et sp. nov., conchs and opercula. Section M, Mt. Scot! Ra., Ajax Lst., UNEL1872. A-D, SAMP30897, conch. A, ventral view, stereo-pair, x50. B, oblique ventral view, x50. C, detail of A, x500. D, detail of B, x250. E,F, SAMP30898, conch, x50. E, dorsal view. F, lateral view. G-I, SAMP30899, operculum, xlOO. G, stereo-pair. H, oblique lateral view. I, dorsal view.
EARLY CAMBRIAN FOSSILS, S. AUST.
225
Fig. 153. Hyptiotheca karraculum Bengtson, gen. et sp. nov., conchs. All x50, except where otherwise stated. A, stereo-pair. A-D, SAMP30900. Mt. Scol! Ra., Ajax Lst., UNEL1872. A, ventral view. B, oblique apertural view. C, lateral view. D, detail of C, x500. E-H, SAMP30901. Horse Gully, Parara Lst., UNEL1856. E, ventral view. F, lateral view. G, detail ofE, x500. H, detail ofF, x250. I-L, holotype, SAMP30902, Curramulka,Parara Lst., UNEL1 846. I, oblique ventral view. J, lateral view. K, oblique dorsal view. L, detail of K, x500.
226
STEFAN BENGTSON et al.
Fig. 154. Hyptiotheca karraculum Bengtson, gen. et sp. nov., conch. SAMP30903, Curramulka, Parara Lst., UNEL1763b. A, ventral view, x50. B, lateral view, x50. C, oblique apertural view, x50. D, detail of shell structure at the edge of broken portion on dorsal side (top right in B), x500.
referring to the type occurrence in The Hum mocks, Kulpara. Material. Holotype SAMP30892 (Fig. 149A-C) a conch, from 6529RS105, Kulpara, Parara Lst.; paratypes 14 conchs and nine opercula. Distribution. Kulpara, Parara Lst. (6529RS105106).
Diagnosis. As for the genus. Description. Conchs up to 1.2mm long, but larger opercula (Fig. 151) suggest maximum length of at least 2.5mm. There is no dorso
ventral curvature. The transverse cross-section is lenticular, with the dorsal surface more convex than the ventral one, and the two forming a weak lateral angle (Fig. 149B,D,F). The dorsal side has
EARLY CAMB RIAN FOSSILS, S. AUST.
227
Fig. 155. Hyptiotheca karraculum Bengtson, gen. et sp. nov., opercula. All x50. A,D,G,I, stereo-pairs. A-C, SAMP30904, Horse Gully, Parara Lst., UNEL1 762. A, outer view. B, oblique lateral view. C, dorsal view. D-F, SAMP30905, Curramulka, Parara Lst., UNEL1848. D, outer view. E, oblique lateral view. F, dorsal view. G,H, SAMP30906, Horse Gully, Parara Lst., 6429RS 107. G, inner view. H, oblique lateral view. I, Horse Gully, Parara Lst., UNEL1852. Inner view.
228
STEFAN BENGTSON et al.
Fig. 156. 'Hyolithes' conularioides Tate, 1892, steinkem of conch, SAMP30907, H orse Gully, Parara Lst., UNELl852. All x20. A, dorsal view, stere o-pair. B, dorsolateral view. C, oblique apertural view.
a faint median ridge (Fig. 1 49C,F). The ligula is semi-elliptical, about three times wider than long. The dorsal apertural edge is in one plane. The surface sculpture consists of transverse striations parallel to the growing margin, as well as weak, irregular, approximately longitudinal wrinkles (Fig. 149A). The protoconch is bulbous with a pointed apex, and separated from the rest of the conch by a constriction about 200fJ.m from the apex. Co-occurring opercula (Figs 150, 151) have a crescentic cardinal shield and poorly defined tectula. The conical shield is strongly convex. Cardinal processes are short, diverging at c. 4050°. One pair of short clavicles is situated at the junction between cardinal and conical shields, and ends in blade-like projections inside the mouths ofthe tectula (e.g., Fig. 151 C). Although not found in place in the conchs, the opercula only occur with the conchs described here, and their morphology also supports their association.
Hyptiotheca Bengtson, gen. novo Etymology. Greek hyptios, lying on the back, and theke, sheath; referring to the probable orienta tion of the conch with dorsal side down.
Type and only species. Hyptiotheca karraculum Bengtson, sp. novo Distribution. Lower Cambrian, South Australia. Diagnosis. Conchs with ovoid cross-section and ventrally directed longitudinal curvature. Ligula semi-elliptical, at 120° to dorsal apertural mar gin. Surface sculpture of distinct growth lines and faint longitudinal striations. Opercula with broad cardinal shield, well-defined tcctula, car dinal processes about 1/4 length of the oper culum width, thickened central field on inner surface, and no clavicles.
Hyptiothecakarraculum Bengtson, sp. novo (Figs 152-155)
Etymology. Anagram of Curramulka, the type locality. The name is to be treated as a noun. Material. Holotype SAMP30902 (Fig. 153I-L) a conch, from UNEL1846, Curramulka, Parara Lst.; paratypes c. 50 conchs and 10 opercula. Distribution. H o rs e G u l l y , P a ra r a L s t . (UNEL1852-1854, 1856, 642 9RS107); Curra-
Fig. 157. Triplicatella disdoma C onway Morris, gen. et sp. novo Curramulka, Parara Lst., UNELl763b (A-C), UNELl848 (D-H); H orse Gully, Parara Lst., UNELl854 (I,J); UNELl764 (K). A,B, SAMP30908. A, dorsal view, x60. B, oblique lateral view, x60. C, SAMP30909, ventral view, x40. D-F, h olotype, SAMP30910. D, la teral view, x60. E, anterior view, x60. F, dorsal view, x60. G,H, SAMP309 11. G, lateral view, x60. H, posterior view, x60. I,JJ SAMP30912. I, anterior view, x120. J, lateral view, x120. K, SAMP30913, dorsal view, x60.
EARLY CAMBRIAN FOSSILS, S. AUST.
229
230
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
mulka, Parara Lst. (UNEL1845-1849); Mt. Scott Ra., Ajax Lst. (UNEL187l?, 1872-1874).· Diagnosis. As for the genus. ., Description. Conchs are up to 3mm long, ovoid in transverse cross-section, with dorsal side more convex than ventral. The ligula is semi-elliptical, about 2.5-3 times wider than long. The dorsal and ventral apertural edges meet at c. 120° (Figs 153J, 154B). Longitudinal curvature of conch is ventraL Surface ornamentation consists of distinct transverse growth lines, slightly terraced toward the apex (Figs 153D,L, 152C). A faint and 'dense longitudinal striation may also be visible (Figs 153D,L, 154D), apparently reflecting the orien tation of acicular structural elements in outer part of the shell wall (Figs 152C, 154D). Thicker phosphatized walls reveal an inner layer of plate like elements arranged parallel to growth lines (Fig. 153G). The protoconch is bulbous with a pointed apex, and separated from the rest of the conch by a constriction about· 200 J.Lm from the apex (Figs . 153H, 152D). Opercula (Figs 152G-I, 155) are ovoid, with a broad cardinal shield and well defined tectula. The cardinal processes are c. 1/4 as long as the width of the operculum. There are no clavicles. The inner surface (Fig. 155G,I) has a thickened central part that may carry faint radial striations (Fig. 155G). No in-place associations of conch and operculum have been found, but the two largely co-occur, and there is a good morpho logical fit between them. Biology. Ventrally concave curvature such as in Hyptiotheca is not common among hyoliths. Marek (1963) even reported Hyolithes sp. from the Middle Devonian of Bohemia in which lon gitudinal curvature mostly is ventrally convex and straight, but where also rare cases of dorsally convex forms occur. Hyoliths are generally as sumed to"have been lying on their ventral, con vex or straight, side (Marek & Yochelson, 1976; Runnegar et al.,1975), an interpretation sup ported by cases of epizoan encrustation on hyolith conchs (Marek & Galle,1976) A lon gitudinal curvature in the opposite direction may �
231
indicate that such forms rested on the dorsal side. · Although other life attitudes are possible; this seems the most straightforward interpretation of Hyptiotheca's unusual conch shape. 'Hyolithes' conularioides Tate,1892 (Fig. 156) [SB, BJC] 1892
Hyolithes conularioides Tate, p.186, p1.2, fig.l,la.
Material. C. 60 conchs. Distribution. Horse Gully, Parara Lst. (UNEL 18 52-18 53, 64 29RS109, 6429RS112-113); Curramulka, PararaLst. (UNEL1849, 1851); Mt. Scott Ra., Ajax Lst. (UNEL1869). Description. Mostly steinkerns of conchs up to 5mm long, with an angle of diverge,nce view) that increases from c. 20° to c. 50° towards · the aperture. The ventral side is flat or concave; the lateral sides rounded, and the dorsal side roof-like with a distinct median sulcus. The ini tial part is slightly bulbous, with a pointed tip near the ventral side. Comparisons. The holotype (Tate, 1892, fig.1) differs from the internal moulds described here in having sharp lateral edges, a divergence angle decreasing with growth, and a flat ventral sur face. Restudy of Tate's material (twospecim;e1is) from Curramulka indicates thdt the lateral edges are not as constricted as his illustration suggests, that the angle of divergence in the early growth stages cannot be determined, and that the ventral side cannot be observed in either specimen� In view of the distinctive dorsal furrow and general shell shape, there seems to be little doubt thatour specimens belong to Tate' s species. Class, Order, Family uncertain [SCM] Triplicatella Conway Morris, gen. nov. Etymology. From the three-fold plicaii. onof one, and occasionally both sides. Type species. Triplicatella disdoma Conway . Morris, sp. nov..
-
Fig. 158. Triplicatella disdoma Conway Morris, gen. et sp. novo Kulpara, Parara Lst., UNEL1860 (A-F); Mt. Scott Ra., Ajax Lst., UNEL1871 (G-K), UNEL1766 (L�N). A,B, SAMP30914. A, dorsal view, x90. B, posterolateral view, x90. C,D,SAMP30915. C, dorsalview, x90. D, oblique lateral view, x90. E,F,SAMP30916. E, an ' terior dorsal view, x90. I-K,SAMP30918. I, veritral view,x40. J, posterior view of ventral side, x40. K, pitted area (?musc1e scar) on ventral surface, x120. L....,N,SAMP30919. L, . dorsal view, x40. M, ?anterior view, x60. N, fold on shell margin,x300. .
232
STEFAN BENGTSON
et
at.
Distribution. Lower Cambrian of South and central Australia. Diagnosis. Bilaterally symmetrical, operculum like, centrally located proloculus and broad rim secreted by marginal increments. One side bear ing three folds forming prominent sulci on mar gin. Opposite side bearing single prominent fold, very occasionally three folds. Dorsal surface may bear concentric growth lines and radial or namentation, ventral surface smooth except for pitted areas representing possible sites of muscle attachment. Triplicatella disdoma Conway Morris, sp. novo (Figs 157, 158)
Etymology. Latin dis, no and domus, home; refer ring to the uncertain position of this form. Material. Holotype SAMP30910 (Fig.157D-F), from UNEL1848, Curramulka, Parara Lst.;' 11 figured paratypes and c. 100 other specimens. Distribution. Curramulka (UNEL1846-1849, 1851), Horse Gully (UNEL1852-1854, 1856, 6429RS106-112), Parara Lst.; Mt. Scott Ra., Ajax Lst. (UNEL1866, 1869,_1871, 1873, 1874).
dued. Rare crushing (Fig. 157G, H) may be ac cidental or result from predation. The concave ventral surface may bear subdued radial impressions as well as an elongate depres sion, flanked by low ridges, on either side of the anterior fold (Figs 157C, 158E,F ,I,J). Pitted zones between the prolocular area and either the anterior or posterior folds also occur (Fig. 1581K). Secretory tissue presumably mantled this side, with the pair of elongate depressions per haps representing muscle scars. The significance of the pitted zones is less c�rtain, but they may mark another area of muscle attachment. Shape and putative muscle scars are suggestive , of an opercular function. T. disdoma resembles superficially hyolith opercula, but none of the latter possess comparable anterior and posterior folds. In addition, no hyoliths from our samples have an apertural margin corresponding to the crenulated margin of this fossil, and the' other tubular fossils have simple apertures. T. disdoma recalls Mobergella, in which a postulated oper culate function could not be matched to any tubicolous fossil (Bengtson, 1968). The pos sibility that T. disdoma is part of a larger scleritome is worth consideration.
MOLLUSCA
Diagnosis. As for the genus. /)escription. Primary composition of these fos sils is probably calcium carbonate, as seen in thin sections. That the frequent phosphatization was diagenetic is inferred from 1, polished and etched sections which show the phosphate to have a blocky ultrastructure without growth lines, and 2, epitaxial coats (Fig. 158N). The operculum-like fossils are broadly con cave-convex discs (Figs 157 A,C,F,K, 15.8A, C,H,I,L). The convex surface is taken as dorsal, and its centre is occupied by a small proloculus like structure. Three prominent folds on one side (Figs 157B,J,K, 158B,D) are arbitrarily taken to , be posterior and provide the most obvious indica tion of bilateral symmetry. These folds may be traced from dose to the proloculus, although in the smallest specimens they are effectively ab sent (Fig. 158H). They are of about equal amplitude, and on the shell margin form prominent sulci. On the opposite" anterior side there is usually a single- prominent fold (Figs 157B,D,E-I,K, 158A,D, G,H), although very oc casionally a 3-fold arrangement occurs (Fig. 158L,M). , The dorsal surface bears concentric: growth lines (Figs 157A,F,G,K, 158C), indicating mar ginal incrementation. Radial ornamentation may be present (Figs 157B,D, 158H), normally sub-' '
[BNR]
Early Cambrian limestones of South Australia bristle with ,e xceptionally well-pre served micromolluscs. They commonly occur as phos phatic internal moulds, but thin (5-10j.Lm) phos phatic coats are also found at some localities. These are both robust enough to survive dissolu tion of the underlying 'carbonate shell and thin enough to replicate faithfully the outer or inner surface of the shell. Thus phosphatic coats pro vide a proxy view of the shell exterior, either as a positive copy (Fig.165A) or as a microscopic negative external mould (Fig. 172B). Distance between coat and steinkern was used to estimate shell thickness in some cases (Fig.172A). Fidelity of phosphate as a medium for pres ervation is well illustrated by fossils of many phyla in the Parara Lst. The secondary phosphate was deposited in thin layers (Fig.166D,F) and has penetrated even the smallest cavities such as the space occupied by the cells in echinoderm ste'reom tween the component parts' of chancelloriid scledtes (Fig. 174F,G). In studying micrornolluscs, if is important to try to find each taxon in both microfossil residues al1d ' thin-sections. Phosphatic internal moulds may give an erroneous impression of the external ' form 'of the shell.
EARL Y CAMBRIAN FOSSILS. S. AUST.
This discrepancy is well illustrated by Mackin nonia davidi gen. et sp. novo which has a smooth exterior and a comarginally rugose interior (Fig.159). Most Cambrian molluscs had aragonitic shells, and shells of this type are invariably replaced by or converted to coarsely crystalline calcite in the South Australian l imestones (Fig.166), in con trast to the orginally calcitic fossils which retain their original microstructure (Fig.174C-E). There are, however, several ways of determining the nature of the original skeletal materials (Run negar, 1985b). The best source of information comes from the surfaces of ultra-fine-grained phosphatic internal moulds. Such surfaces may have replicated the topography of the original shell microstructures prior to diagenetic altera tion of the aragonite to calcite (Figs 159D,G, 1600, 161J, 165G, 169B). Rarely, some relict of the original fabric may be visible in the largely recrystallized carbonate of the shell (Fig.159E). And in some cases, the original aragonite crys tallites have been either replaced by or coated with fine grained apatite (Fig.170). Finally, it may be possible to determine the nature of the original shell microstructure by examining natural casts of the tunnels cut by microscopic endoliths (Fig.lO). These may show traces of the shapes of the crystallites that formed the shell (Runnegar, 1985b). Most Cambrian micromolluscs are univalves of uncertain affinities. Almost all have been referred to the Monoplacophora (Runnegar & Jell, 1976; Runnegar, 1983), thus expanding the original concept of the class to embrace most or all stem group molluscs that possessed an un divided shell (Conchifera). This view has been criticised by those who prefer a narrower defini tion of the Monoplacophora (e.g., Wingstrand, 1985), but the matter is beyond the scope of this monograph and will be dealt with elsewhere. For the Rresent, the term Monoplacophora is used in the wider sense of Runnegar & Jell (1976). Early and Middle Cambrian micromolluscs that were first identified locally have proved to be widespread. A good example is Yochelcio nella Runnegar & Pojeta, described originally from Australia, and subsequently identified in eastern N o r t h A m e r i c a ( R u n n e g a r & Pojeta,1980; Peel,1987), Kazakhstan (Missar zhevsky & Mambeto v,1 9 8 1 ) , the U.K. (H inz,198 7 ) , D enmark (Berg-Madsen & Peel,1987), Spain (Geyer,1986) and China (Pei, 1985). As a result, it is becoming clear that micromolluscs may be used to support other taxa in zoning and dating the Early and Middle Cambrian. The early Palaeozoic micromollusc faunas of Australia and China are particularly closely related, but it is also clear that micro-
233
molluscs were able to disperse rapidly and wide ly in the Early Cambrian. Phylum MOLLUSCA Cuvier,1797 Subphylum CYRTOSOMA Runnegar & Poje ta, 1974 Class MONOPLACOPHORA Knight,1952 Order CYRTONELL�DA Horny,1963 Superfamily HELCIONELLOIDEA Wenz, 1938 Family HELCIONELLIDAE Wenz,1938 Mackinnooia Runnegar, gen. novo Etymology. For David I. MacKinnon, University of Canterbury, one of the few austral students of Cambrian molluscs. Type species. Mackinnoniadavidi Runnegar, sp. novo Diagnosis. Microscopic, bilaterally symmetri cal, cyrtoconic univalves with a smooth exterior; interior of shell with three or four rounded thick enings running parallel to the shell margin on the lateral and posterior flanks; a single transverse thickening beneath the beak; outer shell layer composed of lOflm-thick fibres approximately normal to exterior surface. Remarks. The holotype of the type species of Latouchella Cobbold,L. costata, appears to have been misplaced w h i l s t on loan from t h e Sedgwick Museum, Cambridge, and so the con cept of Latouchella must be based on Cobbold's (1920, p1.24, figs 41,42) inadequate drawing of the specimen. Nevertheless, it appears that L. costata must have been corrugated externally like many other species that have been referred to Latouchella (Runnegar & Jell,1976; Geyer, 1986). That being so, Mackinnnonia resembles Latouchella in many respects, but differs in having a smooth exterior. Oelandia Westerg§rd is similar toLatouchella in being externally cor rugated, but differs from both Latouchella and Mackinnonia in having the corrugations inter lock across the periphery of the shell (Peel & Yochelson,1987). Mackinnonia davidi is similar to the species described here as Leptostega? corrugata. This gradation in form highlights the problem of recognizing discrete taxa at all levels in Early and Middle Cambrian faunas. However, the better known species of Latouchella (e.g., L. orientalis (Walcott,1905), L. arguta (Resser, 1939) L. ac cordionata Runnegar & Jell,1976, L. merino Runnegar & Jell,1976, L. iacobinica Geyer, 1 9 8 6 , L. holmdalense P e e l , 1 9 8 8 , a n d L. pearylandica Peel,1988) form a cohesive group that displays less intrageneric variability than
234
STEFAN BENGTSON et al.
would occur if Mackinnonia davidi or Leptos tega? corrugata were .placed in Latouchella. Ideally,type species should represent nodes in a morphological continuum, and if the nodes are subsequently found to be too close together,it is a simple matter to submerge the younger names i n to synonymy. For the present, it seems desirable to. separate forms such as Leptostega, Oelandia and Mackinnonia from Latouchella. Ma�kinnonia davidi Runnegar,sp. nov.(Figs 159,160J)
Material. Holotype SAMP29013 from UNEL 1761,Horse Gully,PararaLst; hundreds of other p h o s p h a t i c internal moulds from U NE L 1761/1856,1762/1854,Horse Gully,PararaLst., UNEL1871-3,1877,1766c,Mt. Scott Ra.,Ajax Lst.
Diagnosis. 'Helcionellid with the following spe cial characteristics: shell narrow, triangular in side·view with apex only slightly inclined back wards; sides only slightly convex; surface with strong concentric ribs which alt.ernate on the narrow sides [of the shell] or grade irregularly into each other' (translated from Geyer,1986, p.84). Leptostega? corrugata Runnegar,sp. nov. (Fig. 160A-G).
Etymology. Latin,corrugatus, wrinkled.
.
Description; Known both from numerous phos phatic steinkerns and in thin section. Shell up to c. lmm in size,bilaterally symmetrical,laterally compressed,cyrtoconic,with prominent comar ginal thickenings on lateral(Fig. 160J) and con vex flanks (Fig. 159C). An obvious transverse thickening beneath the beak (Fig.159C) is reflected as a notch on the internal mould (Fig.l59A). In contrast,the outer surface of the shell \Vas smooth (Fig. 159C,G). E nlarged views of internal moulds(Fig. 159H) normally show the casls of shell prisms on the areas corresponding to the thinner parts of the shell; the intervening areas (grooves on the internal moulds) are smooth(Fig. 159D). One exceptional thin section appears to have relict prisms preserved in the outer shell wall (Fig.159E ); these are narrower (3f.Lm) than marks left by the ends of the prisms on steinkerns(10f.Lm). .
Material. Holotype SAMP29006, UNEL1763c, Curramulka,Parara Lst.; many phosphatic inter n a l m o u l d s f r o m UN E L 1 7 6 3 b / 1 8 4 6 , 1763c/1848, 1849�51,Curramulka,Parara Lst.; UNELI869, 1871, 1766c, Mt. Scott Ra., Ajax Lst.; UNEL1764, Bunyeroo Gorge, Oraparinna Shale. Description. K nown only from phosphatic steillkerns. Shell c. 1mm or less in' size, bilat erally symmetrical, cyrtoconically curved, with about five comarginal thickenings that continue around the shell (Fig�160F). Outer shell surface unknown. E nlarged views of internal moulds show the casts of the ends of outer-layer shell prisms on the parts of the mould where the shell wasthin(Fig. 160D). The casts of the comarginal thickenings are smooth.
Remarks. Mackinnonia davidi is distinctive and abundant. There is no obvious difference be tween specimens from different levels in the Parara and Ajax limestones. -
Remarks. Internal moulds of L. irregularis -from the Middle Cambrian of Spain {Geyer,1986)are similar to L? corrugata iri many respects. How ever, by analogy with M. davidi, it is likely that the exterior of L? corrugata was smooth. If so, L? corrugata should be transferred to Mackin nonia. In the meantime,it is tentatively placed in Leptostega beca'use of the close similarites in the internal moulds. L? corrugata differs from L. irregularis in having narrower and higher inter nal corrugations. .
Leptostega Geyer,1986
Family UNCERTAIN
Type species. 'Leptosiega irregularis Geyer, 1986,Middle Cambrian, Spain; by original designation.
Pararaconus Runnegar,gen. novo .
.
.
Etymology. For the Parara Lst. "
Fig. 159. Mackinnonia davidi Runnegar, gen. et sp. nov., Horse Gully, PararaLst. A, :holotype, phosphatic internal mould viewed from left side�SAMP29013, x35. B, left side of topotype, SAMP29014, x35. C, sagittal section of shell in plane polarized light, x45. D, enlargement of A showing casts of ends ofprisms of outer shell layer on convex parts of internal mould, x150. E, thinsection of outer part of shell showing outlines of prisms of outer shell layer in cross-polarized light, x300. F, posterior view of internal' mould, AMF61838, x70. G, section of shell cut perpendicular to plane of symmetry, xl00. H, enlargement of F showing casts of ends of prisms of outer shell layer, x500.
EARLY CAMBRIAN FOSSILS, S. AUST.
235
236
STEFAN BENGTSON etal�· /
Type species. Pararaconus staltorum. Runnegar, sp. novo
have a flared aperture. Prominent ridges on each side of the mould (Fig.161A-C) correspond to depressi.�ns Diagnosis. Smooth, bilaterally symmetical, surface of these ridges and the flared edges of the laterally compressed, conical shells that have a shell are normally covered with polygonal eleva widely flared aperture and a pair of internal tions that seem to correspond to the ends of shell . lateral depressions that expose the ends of the prisms (Fig.161D-F). However, hi contrast to prisms of the outer shell layer. the similar structures in Mackinnonia and Lep tostega? corrugata, the structures in P. staitorum Remarks. This odd fossil is unlike most other are elevations rather than depressions. Some shells that are referred to the Mollusca. It is not specimens have adhering phosphatic casts of the certainly a mollusc, but it has a recrystallized tunnels of microbial endoliths (Fig.161C). calcareous shell (Fig.161H) like associated mol Remarks. P. staitorum is a distinctive microfossil luscan taxa'such as Pojetaia (Fig.166B), and it even if it is not a mollusc. also displays a r eplica ted microstructure (Fig. 161D-F) thatseems to be homologous with similar. structures in Mackinnonia and Leptos Family YOCHELCIONELLIDAE Runnegar tega? corrugata.· For all of these reasons it is & Jell, 1976 placed in 'the Helcionelloidea. Y ochelcioneUa Runnegar & Pojeta,1974 Pararaconus staitorum Runnegar� sp. nov. . Type ·species. Yochelcionella cyrano Runnegar (Fig.161) , & Pojeta,1974, early Middle Cambrian, Austra Etymology. Named:Jor Bryan and Kathi Stait lia; by original designation. who worked together for BR on the, South Diagnosis. Small or microscopic cyrtoconic A�s.,tralian project and 'other matters. univalves with a prominent tube or snorkel on one side of the shell. Material. Holotype SAMP29019,. UNEL1761, Parara Lst ., Horse Gqlly; many other specimens Discussion. Eotebenna Runnegar & Jell,1976 from the type locality (UNEL1761/1856). differs from Yochelcionella in having the snorkel connected to the shell aperture by a na.rrow slit Description. Known from phosphatic internal at the edge of a projecting flange (Runnegar & moulds.and,thin sections (Fig.161G,H)� The in ternal moulds are tall, 'slightly curved cones that. Jell, 1976)� I� Eurekapegma MacKinnon, the .
.
.
Fig. 160. A�G, Leptostega? corrugata Runnegar, sp. nov. A, holotype, phosphatic internal mould viewed from left side, SAMP29006 from UNEL1763c, x35. B, dorsal view, SAMP29007 from UNEL1763c; x35. C-F, left ' lateral, posterodorsal and dorsal views, SAMP29007 from UNEL1764, x45, x200, x60, x60. G, right lateral view, UNEL1763b, x35. H, Obtusoconus sp., left lateral view of phosphatic internal mould, SAMP29018 from UNEL1763c, x22. J, Mackinnonia davidi Runn�gar, sp. nov., oblique thin section of posterior part of shell, UNEL1761, xl00.
Fig. 161. Pararaconus staitorum sp. nov., UNEL1761, Horse Gully, Parara Lst. A, holotype, right lateral view of phosphatic internal mould, SAMP29019, x35. B, anterior view of internal mould, SAMP29012, x40. C, left lateral view of internal mould covered with casts of the tunnels of the endolith Endoconchia, SAMP29015, x35. D, enlargement of A showing casts of ends of prisms of outer shell layer, x175. E; enlargement of right side of internal mould showing casts of ends of shell prisms, SAMP29020, x35. F, J, anterior margin of specimen illustrated in E showing casts of ends of shell prisms, x120, x700. G,H, thin section of shell in plane and cross polarised light showing smooth interior and exterior walls and coarsely recrystallized calcite, x45.
Fig. 162. A, Yochelcionella chinensis Pei, 1985, SAMP29021 from UNEL1764, Oraparinna Shale, Flinders Ra., x35. B- E,H, Stenotheca sp., UNEL1764. B, right lateral view of internal mould, SAMP29022, x60. C, left lateral view, SAMP29023, x35; D,E, anterior and left lateral views of internal mould, SAMP29046, x70. H, left lateral view, SAMP29010, x45. F,G, Proplimi? sp., left lateral and dorsa' views of phosphate replicas of exterior of shell, SAMP29046 from UNEL1763c, x35 and SAMP29052 from UNEL1763b, x45. I,J, Proplina sp., apertural and anterior views of phosphate-coated specimen, AMF61835 from UNEL1766c, x40. K,L, Eocyr toUtes? sp., dorsal and left lateral views of phosphatic internal mould, SAMP29047, UNEL1764, x35.
EARLY CAMBRIAN FOSSILS, S. AUST.
237
238
STEFAN BENGTSON etal.
Fig. 161
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 162
239
240
STEFAN BENGTSON et al.
Fig. 163
EARLY CAMBRIANFOSSILS, S. AUST.
Fig. 164
241
242
STEFANBENGTSON etal.
Fig. 165
EARLY CAMBRIAN FOSSILS, S. AUST.
flange is separated from the 'body chamber' by a plate that runs across the ventral part of the shell (MacKinnon, 1985). Thus each of these genera maintained a passage to (or from) the exterior i n the dorsal region of the shell. The function o f the snorkel and its equivalents in Eotebenna and Eurekapegma remains uncertain. Yochelcionella chinensis Pei,1985 (Fig.162A) Material. Two incomplete phosphatic steinkems from UNEL1764, Oraparinna Shale, central Flinders Ra. Remarks. The proportions and shape of the snorkel identify these fragments as Y. chinensis. The two known occurrences of Y. chinensis are approx imately coeval. Family STENOTHECIDAE Runnegar & Jell, 1980 Stenotheca Salter in Hicks,1872 Type species. Stenotheca cornucopia Salter in
243
Hicks,1872, M i ddle Cambrian, Wales; by original designation. Diagnosis. Tall, slightly cyrtoconic, laterally compressed univalves, subtriangular in lateral view. Remarks. The type species of Stenotheca was redescribed by Cob bold (1934), but the syntypes have since been misplaced whilst on loan from the Sedgwick Museum, Cambridge. However, it appears to be closely related to S. acutacosta Walcott,1890 from the Brigus Formation of southeast Newfoundland (Fig. 163J-L), and so that species is asecondarystandardf or the genus. Stenotheca d i ff e r s from Anabarella Vos tokova, 1962 principally in the degree of coiling of the shell. However, in Anabarella the shell is inv olute in the sense that there is no space b e n e a t h the apex (Fig.163A) whereas in Stenotheca the beak is well separated from the growing margin of the shell (Fig.163D). None theless, forms such as A. simesi (MacKinnon, 1985) andA. drepanoida (He etal., 1984) which are known only from internal moulds, may be difficult to categorize.
Fig. 163. Anabarella Vostokova, 1962 and Stenotheca Salter in Hicks, 1972, Parara Lst., Horse Gully. A, Anabarella allstra/is Runnegar, sp. nov., oblique ventral view of internal mould and incomplete phosphate coat; note authigenic pyrite grain and endolith, SAMP29054, UNEL 1761, x70. B-G, M,N, Stenotheca cf. drepanoida He & Pei i1 He et al., 1984. B, left side of phosphatic internal mould, AMF61836, UNELl762, d5. C, right side of internal mould, SAMP29055, UNELl852, x50. D, internal mould with adhering phosphate coat, SAMP29056, UNELl762a, x35. E, interior ofphosphatic external mould showing exterior ornament in negative relief, SAMP29057, UNELl761, x50. F, posterior view of partly coated internal mould, SAMP29058, UNELl852a, x60. G, anterior view of internal mould, SAMP29059, UNELl762a, x60. M,N, ventral and left lateral views of partly coated internal mould, SAMP29060, UNEL1852, x80. H-L, Stenotheca aClltacosta Walcott, 1890, Brigus Fm., Early Cambrian, Conception Bay, Newfoundland. H, external mould showing exterior ornament in negative relief for comparison with E, USNM18301D, x2. J,K, right lateral and posterior views of internal mould, USNM307733, x8. L, left lateral view of external mould, USNM307731, x 10.
Fig. 164. A-G, Anabarella allstralis Runnegar, sp. nov., Horse Gully, Parara Lst. A, phosphate-coated shell
in right lateral view, SAMP29024, UNELl761, x60. B, phosphate-coated shell in left lateral view, SAMP29016, UNEL1761, x50. C, right lateral view of phosphatic internal mould, AMF61834, UNEL1761, x40. D, holotype, left lateral view of phosphatic internal mould, SAMP29017, UNELl761, x60. E, left lateral view of internal mould, SAMP29025, UNELl761, x60. F, right lateral view of internal mould, SAMP29027, UNELl761, x60. G, oblique-ventral view of phosphate-coated shell, SAMP29029, UNELl852, x80. H-N, Ana barella arglls Runnegar, sp. nov., UNELl778, Ajax Lst., Mt. Scott R a . H, dorsal view of phosphatic internal mould, AMF61840, dO. J, holotype, left lateral view of phosphatic internal mould, SAMP29033, x40. K, left lateral view of internal mould, SAMP29032, x30. L, left lateral view of internal mould, SAMP29034, x30. M, left lateral view of internal mould, AMF61821, x40. N, enlargement of J showing casts of erxls of prisms of outer shell layer near edge of mould, xl00.
Fig. 165. Pojetaia runnegari Jell, 1980, Horse Gully, Parara Lst. A, broken phosl?hatic coat a n d partly exposed
phosphatic internal mould of right valve, SAMP29035, UNELl761, x80. B, thm section of posterior part of shell showing ligament attachment areas and dark phosphatic coat, plane-polarized light, UNELl761, x 100. C,
phosphatic coat of right valve, AMF61805, UNEL1761, x80. D, oblique view of dorsal margin of phosphate coat of right valve, SAMP29037, UNELl762, x80. E-G, internal mould of left valve showing casts of shell prisms, electronically inverted in G, SAMP29026, x80, x500, x800.
244
STEFANBEN GTSON e r a l ,
Stenotheca cf. drepanoida (He & Pei i n H e e t al., 1984 (Fig. 163B-G,M,N) Material. Many internal moulds and specimens with adhering phosphate coats from the Parara Lst. at Horse Gully (UNELl761, 1762, 1762a, 1852) and Curramulka(UNEL1849 ), and Ajax Lst., Mt. Scon Ra. (UNEL1873, 1874, 1876). Description. Shell mm, laterally compressed, with a beak that overhangs the shell margin; silhouette variable; external ornament of regular ly spaced, angular, comarginal rugae that coalesce anteriorly and widely separated radial ridges (Fig.163E); shell thin; microstructure un known. Remarks. Illustrated specimens of A . drepanoida resemble internal moulds of the South Australian species and also show traces of the regular, com arginal rugae. External ornament of S. cr. drepanoida (Fig. 163E) is close to that of S. acutacosta (Fig.163H) from the late Early Cambrian o( Newfoundland, but that species is less strongly coiled (Fig.163J-L). Stenotheca sp.(Fig.162B-E,H) Material. About 20 fragmentary phosphatic in ternal moulds from UNEL1764, Oraparinna Shale, Buny eroo Gorge. Remarks. These specimens are taller and nar r o w e r from front to back than e i t h e r S.
drepanoida or S. acutacosta. They are similar to S. tepee Runnegar & Jell,1976 from the earliest Middle Cambrian of western New South Wales, but there are too f e w characters to make a posi tive identification with that species. Anabarella Vostokova,1962 Type species. Anabareffa plana Vostokova, 1962, earliest Early Cambrian, Siberia; by original designation. Diagnosis. Laterally compressed, cyrtoconic univalves ornamented with comarginal growth lines. Remarks. Anabareffa differs from Stenotheca in being more strongly coiled and in beinginvolute. Mellopegma Runnegar & Jell,1976 has some of t he characters ofb othAnabarella and Stenotheca in that it is not strongly coiled, but Meflopegma is evolute and has a long aperture that extends dorsally at both ends of the shell. Anabarella australis Runnegar, sp. novo(Figs 163A, 164A-G) Etymology. Latin australis, southern. Material. Holotype SAMP29 017 from UNEL 1761, base of Parara Lst., Horse Gully; hundreds of o t h e r specimens from the Parara Lst. (UNEL1761, 1762a, 1852-4, 1856) and upper most Kulpara Lst. (UNEL1857 ) at Horse Gully,
Fig. 166. Pojeraia runnegari Jell, 1980, AMF61804, UNEL1 761. A, near-sagiual section of shell, plane polarized light, showing clear calcite of shell and darker phosphate coat, )[65. B, same as A, cross-polarized
light, showing large single crystals of calcite forming recrystallized shell, )[65. C, same as A viewed by back scallered electrons in a scanning electron microscope; the lighter areas are phosphate and the darker areas are calcite, )[65. D,enlargement of the rectangular area outlined in A showing the fine layering in the phosphate coat, plane-polarized light, Jl:250. E, enlargement of posterior part of shell in B showing that phosphate coat crosses the space between the edges of the valves, Jl:270. F, enlargement of C showing layering in phosphate coat where it bridges the space between the edges of the valves, )[1000.
Fig. 167. Pelagielia subangulara (Tate, 1892), NMVP120790, Kyancutta collection, 'Salrerelia Limestone'
(=Parara LSL), Horse Gully,Ardrossan. A-E, various views of ederior of shell as reflected in thin phosphate coat and partly e)[posed phosphatic replacement of shell, )[50. F-G,enlargements of areas indicated by arrows in C and D showing radially arranged crystallites in the phosphate copy of the outer part of the shell, Jl:230, )[150. H,enlargement of early formed part of shell showing nature of larval shell, )[110.
Fig, 168. A-D,H, Pelagielia subangulara (Tate, 1982). A,B,apertural views of phosphate-coated specimen partly filled with phosphatic matri)[,SAMP29038,UNELI762,)[40, )[80; arrow points to thickened part of shell that is frequently covered with shallow pits on internal moulds. C, dorsal view of phosphate-coated shell with
prominent auricle, SAMP29039, UNEL1762, )[60. D, dorsal view of internal mould partly covered with phosphate coat, SAMP29031, UNEL1761,d5. H, internal mould, SAMP29036,UNEL1761, d5. E- G,J,K, Pela gielia adunca ( He & Pei,1984). E,G, dorsal and lateral views of internal mould QMF181 03,UNELI762, )[35. F,dorsal view of incomplete internal mould, SAMP29041,UNELI874,)[45. J,K, internal mould with well marked comarginal furrow caused by interruption in shell growth, AMF61837, UNELI762, )[60.
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 166
245
246
STEFAN BENGTSON et al.
Fig. 167
EARLY CAMBRIAN FOSSILS, S. AUST.
Fig. 168
247
248
STEFANBENGTSON et al.
Fig. 169
EARLY CAMBRIAN FOSSILS, S. AUST.-
Fig. 170
249
250
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
251
Parara Lst. at Curramulka (UNEL1763c, 1846, 1848-9), and the· Ajax Lst., Mt. Scott Ra. (UNEL1872, 1873, 1876).
1778; middle of Ajax Lst., Mt Scott Ra.; tens of other specimens from the same locality and younger UNEL1869.
Description. Known from phosphatic internal moulds (Fig.164B-F), phosphate coats of the exterior (Fig.164A,G) and thin sections. The shell is
Description. Known only from phosphatic inter nal moulds. The shell is compres�ed laterally (Fig.164H), the beak overhangs the edge of the shell aperture, and there is a crescentic notch between the beak of the steinkern and its aper tural edge (Fig. 164J-M). Casts of prisms near the margins of the internal moulds (Fig. 164N) sug gest that the outer shell layer was prismatic as in Mellopegma georginensis (Runnegar,1985b).
IJemarks. The silhouette of the internal mould is the most distinctive feature ofA. australis distin. guishing this species from A. argus sp. nov. (Fig.164H-N) and probably from the type species. A. simesi from the late Middle Cambrian of New Zealand (MacKinnon,1985) is also dif ferent in shape. Anabarella argus Runnegar, sp. novo (Fig. 164H:-N) . Etymology. Latin Argus, the hundred-eyed guar dian of 10; also the source of funds for much of this work (ARGS). Material. Holotype SAMP29033 from UNEL
Remarks. See comments under A. australis.
Order TRYBLIDIIDA Lemche,1957 Family TRYBLIDIIDAE Pilsbry, 1899 °Proplina? spp. (Fig.162F,G,I,J) Remarks. Cap-shaped shells like the specimens illustrated here are found at a number of locali ties. Most are incomplete phosphatic internal moulds of larger shells and very few have any distinctive characters. Of the large number of names that may be available for such taxa, Propiina Kobayashi,1933 has the advantage of priority.. Distinctive external ornament· (Fig: 162F,G) should enable identification elsewhere. The smooth form· (Fig. 1621,J) may be allied,to . Protowenella cobbensis (MacKinnon, 1985). ,.
Fig. 169. A-F, H-K, Pelagiella subangulata (Tate, 1892), Parara Lst, Yorke Peninsula. A, incomp1ete specimen
comprised of phosphatic internal mould, phosphate-replaced shell and phosphate coat, showing growth lines, spiral ridges and radial crystallites ofouter shell layer, SAMP29043, UNEL1763c; x40. B, replicated microstruc ture on the outer part of the whorl of a phosphatic· internal mould, SAMP29053, UNEL1761, x1800.C, surface of phosphatic internal mould showing comarginal grooves t�ought to represent casts of crystallites of middle or inner shell layer, SAMP29042, UNEL1763c, x600. D-F, three views of phosphate-coated shell, SAMP29030, UNE�1761, x50. H-K, rubber copy of lectotype, showing ridge on flattened surface of whorl and spiral ornament near whorl periphery, SAMT1234a, x30, x30, x70. L, enlargement of phosphate· coat at whorl periphery, SAMP29039, x140. G, Pelagiella atlantoides (Matthew, 1894), USNM298724, late Early Cambrian Hanford Brook, St John Co., New Brunswick, Canada, x5.
Fig. 170. Microstructure of Pelagiella. The photograph on the left (enlargement from Fig. 92A) shows a thin phosphate coat overlying phosphate copies of the crystallites of the outer shell layer. Note the growth lines (1), the spiral ridges (2) and the radially arranged crystaIlites (3); crystallites enlarged in lower right photograph x900. The upper right photograph is an enlargement (x850) of the inner surface of a phosphate coat from a Middle Cambrian species of Pelagiella from the United States.
Fig. 171. A-H,J,K, Yuwenia bentleyi Runnegar, 1981, UNEL1761, Horse Gully, Parara Lst. A-D, views of
well-preserved internal mould; note pittipg of parts of surface, AMF61819, x80, x50; x35, x100. E,F, paired pits on surface of internal mould, AMF61801, x200, x850. G, stereo-pair of phosphatic internal mould with piece of phosphatic filling of columella ornamented with casts of comarginal growth lines, SAMP29053, x30� H,K, internal mould with cast of columella showing nature of comarginal growth lines, SAMP29003, x35, x80. J, internal mould with cast of columella of next youngest whorl, SAMP29004, x35. L, Bestashella tortilis Missarzhevsky, 1981, internal mould with adhering cast of endolithic boring, Endoconchia lata Runnegar, gen. et sp� nov., SAMP29001, UNEL1761, x50.
252
STEFAN BENGTSON e t al.
Fig.I72. Microstructure of Yuwenia bentleyi Run negar, 1981. A, part of internal mould showing casts of comarginally disposed crystallites of inner shell layer; phosphate coat (arrow) shows original thickness of shell, SAMP29002, UNEL1761, x250. B, enlargement of phosphatic filling of columella showing ridges formed by growth lines on the surface of the shell (vertical lines) crosscutting impressions of fan-shaped bundles of crystallites of the outer shell layer , SAMP29004, x600.
Kalbyella Berg-Madsen & Peel, 1978
Kalbyella sp. (Fig.162K,L)
Type species. Kalbyella poulseni Berg-Madsen & Peel,1978, Middle Cambrian, D enmark; by original designation.
Remarks. This material, rare in the Oraparinna Shale at UNEL176 4, is more coarsely ribbed than the type species and an unnamed species from the earliest Middle Cam brian of western New South Wales (Runnegar & Jell,1976).
Diagnosis. 'Monoplacophoran with m i nute, elongate cap- shaped shell having apex varying from acute and overhanging, high above the anterior margin to blunt and near the apertural margin. Ornament of numerous radiating ridges crossed by fine growth Iines.'(Berg-Madscn & Peel,1978, p.116). Remarks. Berg-Madsen & Peel introduced Kal byella for a form which Runnegar & Jell (1976) had referred to the Ordovician Helcionopsis UI rich & Schofield. Eocyrtolites Yii is more coar sely ribbed and has a flat zone on the whorl periphery (Yii,198 6).
Order PELAGIELLIDA Runnegar & Pojeta, 1985 Family PELAGIELLIDAE Knight, 1956 Pelagiella Matthew,1 895
Type species. Cyrtolites atlantoides Matthew, 1894, E arly Cambrian, Canada; by original designation. Diagnosis. Microscopic to tiny, dextrally coiled shells with an oval to triangular, flaring aperture.
Fig. 173. A-D, G-L, Ardrossania paveyi Runnegar, gen. et sp. nov., UNEL1761, Horse Gully, Parara Lst. A,D,G,J, various views of the holotype, probably a phosphatised shell, SAMP29028, x95, x95, x145, x145. B,C, lateral and apertural views of another specimen, SAMP29044, x45. H,I,L, progressive enlargements of the apertural edge of the holotype showing how the phosphate has coated the inner and outer walls and filled the spaces between the fibrous crystallites of the shell wall; arrows indicate the same point in each photograph; lines in I show how fibrous crystallites like those in E could have filled voids in I. L x220, I x850, H x3500. K, lateral view of third specimSAMP29045, x30. E,F, part of phosphate- replaced shell of Pelagiella s ubangulata (Tate, 1892), SAMP29043, x 1450, x145; the radial structures are phosphatic copies of fibrous crystals, possibly originally aragonite; they are comparable in size and shape to the structures seen in A rdrossania paveyi.
EARLY CAMBRIAN FOSSILS, S. AUST;
253
254
STEFAN BENGTSON et al.
produce a series of regularly arranged nodes on some parts of the shell (Fig.167C,E). The outer shell layer consisted of fibrous crystals, that are presumed to have been aragonitic, arranged per pendicular to the growth lines and at an angle to the spiral ornament (Figs 167F,G, 170). The inner shell layer appears to' have consisted of comarginally arranged fibrous crystals (Fig. 169C). The aperture was large and oval (Fig.' 168A,B).
Some species have a projecting wing of shell m a t e r i al t h a t. e xt e nd s l a t e r a l l y on t h'e 'pretorsional' left' side of the shell. External or nament of type species unknown but, other species smooth or with various kinds of comar ginal,spiral,zigzag,cancellate or divaricate Cos tae. Shell (pedal) muscles attached to a single muscle scar on left and right sides of the shell; �antle cavity apparently' voluminous and ex tending, beneath the apical region of the coil. Shell apparently originally anigonitic; com-' monly with an inner shell layer of fibrous crystals arranged :approximately parallel to the gro:wth lines and an outer shell layer of fibres lying at right angles to the growth" lines. Some species show traces of an innerrilost foliate structure.
Remarks. The syntypes are not particularly char acteristic but the spe'cimen chosen as a lectotype does'display some of the distinctive ornament (Fig.169K). The species is highly variable in shape, (compare Fig.167A with Fig.168C) and may even grade into the forms identified as P. Remarks. Until the exterior of P. atlantoides is, adunca. The latter is more easily identified from known -fro'm topotypes, ge�eric level taxonomy , internal moulds; in contrast,P. subangulata rep of thePehlgiellidae will remain difficult. 'resents a more general shape that may be found P elagiella ,e�braces many different 'kinds of ' in many distantly related species of the genus. pelagiellids and orily a few distinctive types have been given separate names (e.g�, Costipelagiella Pelagiella adunea ( He &Pei in He et al., Horny,1964). , 1984) (Fig. 168 E-K) Pelagiella subangulata (Tate, 1984 Auriculaspira adunca He & Pei; Zhou & ' 168A-D,169A-F,H-L) -, Xiao, p.138, pl.4, figs 13,14.
1984 A uriculatespira andunca (He & Pei) in He et
1892 Ophileta subangulata T�te, p.184, p1.2, . fig.8a,b.
al., p.352, p1.2, figs 10-15, 19-21.
'
Mater�al. Lectotype ,SAMT1234a, 'Cambrian 'Remarks on nomenclature. The species name was introduced by Zhou & Xiao (1984) as both limestone at Parar�, near Ardrossan', here designated. Also hundreds of internal moulds and' aduca (text) and adunca (plate explanation) and many phosphatic coats from the Parara and Ajax is attributed to He et Pei (MS), 1981. In He et al., Lsts (UNEL1760-2, 1762a� 1763c, 1778, 1822, (1984) the species 'name ,is given as andunca in 1833,1846,1848-50,1856,1860, 1860b,c,1866 both text and figure explanations. However, as -7, 1869-74, 1877); commonjn thin sections. the name is obviously derived from the Latin aduncus meaning bent or hooked, that spelling is De.scription. Upto.c .. 2mm, highly variable in used here. shape, has a rounded whoJI periphery, a convex Material. Numerous specimens from the Parara to concave ,'pretorsional' left flank and a pro LSt., Horse Gully (UNEL1761,1762, 1852, jecting wing or eat at the -extreme right side of the a.pertUre(Fig.168B-D). Ornament consists of ,'1853) and the upper part of the Ajax Lst., Mt. Scott Ra. (UNEL1873,1874, 1876). closely spaced'rounded costae that meet at an , acute angle on the whorl 'peripery (Fig. 169L) Pelagiella with c o n c a ve Description. and which may interfere with the growth lines to .
.
'
,
Fig. 174. Preservation of carbonate skeletons. A, phosphate replica of echinoderm plate, SAMP29040, UNEL1761, x40. B, enlargement of phosphate filling ofechinoderm stereom, UNEL1761, x700. C, echinodenn stereom in thin section, cross-polarized light, xl 00; dark areas are phosphate filling of space originally occupied by tissue. D,E, Pseudorthotheca? sp., oblique thin section showing sharp edges of regular annl,llations of tube and preservation of original calcitic microstructure. D,plane-polarized light, x30. E, cross-polarized light, x80. F, Chancelloria sc1erites in plane-polarized light. The hollow calcareous sc1erites are filled with darker phosphate and some of the phosphate has penetrated the space between the originally separate walls of the , sub units of the lower sClerite, UNEL1761, x40. G, lower sclerite shown in F photographed by back- scattered electrons in a scanning electron microscope, with photograph duplicated and reversed for clarity; the light areas are phosphate and,the darker areas either authigenic quartz (hexagonal shapes) or skeletal carbonate,x140.
EARLY CAMBRIAN FOSSILS, S. AUST.
255
256
STEFAN BENGTSON
et
al.
'pretorsional' left flank, narrowly rounded whorl . periphery, and narrow aperture. Remarks. P. adunca occurs with P. subangulata and may represent one end of a. morphological continuum within that species. However, it is a distinctive morph at least, and is identified separately here for that reason alone.
layer. A previously reported (Runnegar,1985b) prismatic outer layer does not appear to exist. . The shells were bored by, microbial endoliths (Fig.10H) and a number of internal moulds have paired pits scattered· over some of the whorl surface (Fig.171D-F). The origin of these pits is . unknown but they may also have been produced by endoliths, possibly during the life· of the c: animal. '
Class GASTROPODA Cuvier,1797 Subclass ARCHAEOGASTROPODA? Thiele, 1925 Order MACLURITIDA Cox &Knight,1960 Family ONYCHOCHILIDAE Koken,1925 Yuwenia Runnegar,1981 Type species. Yuwenia bentleyi Runnegar; 1981; by original designation.
Remarks. Yuwenia bentlcyi is known only from its type locality. Beshtashella Missarzhevsky in Missarzhevsky &Mambetov, 1981 Type species. Beshtashella tortilis Missarzhev sky in M:issarzhevsky &Mambetov, 1981, Early Cambrian, Kazakhstan; by original designation. ",
Diagnosis. Apparently sinistral but possibly Diagnosis. Microscopic, uItradextral univalve with a low spire, smoothly rounded whorls and a . ultradextral univalve with high whorl translation rate and an oval, flared aperture. tangential aperture that is elongated parallel to the direction of coiling; protoconch not clearly Remarks. Beshtashella is grouped with Yuwenia separated from adult shell. Shell thin, smooth except for growth lines, composed of an inner in the Onychochilidae because of similarities in shell shape (Fig. 171G,L). It is known from only layer of comarginally oriented aragonite fibres and an outer layer of spirally . arranged aragonite two specimens, one from South Australia and the other from Kazakhstan. fibres. Remarks. The only specimen a ttributed t o. Cambrospira Yii,1979 is now known to be a fortuitously shaped phosphatic grain, so Yuwenia becomes one of the oldest representatives of an important lineage of ultradextral Cambrian snails (Runnegar &Pojeta, 1985). Yuwenia dif fers from its younger relatives in having a more 'opsithobranch' - shaped shell. Yuwenia bentleyi Runnegar,1981 (Figs 171A H,J,K,172) Material. C. 20 phosphatic stein kerns from UNEL1761/1856, base of the Parara Lst., Horse Gully; not found in thin section. .
�.
Description. Globose, up to c. 1mm, with a nar row aperture lying parallel to the axis of coiling (Fig: 171G). Phosphatic fillings of the umbilicus (Fig.171J-K) show that the exterior was smooth except for closely spaced comarginal growth lines. Incomplete phosphate coats attached to internal moulds show that the shell was thin (c. 10J.1m; Fig. 172A), and both external (Fig� 172B) and internal moulds (Fig.172A) show traces of the fibrous crystals that formed the shell. They were probably aragonitic and were oriented per pendicular to growth lines in the outer shell layer and parallel to the growth lines in the inner shell
Beshtashella tortilis Missarzhevsky in Missar zhevsky &Mambetov,1981 (Fig.171L) Remarks. A single specimen was recovered from the base of the Parara Lst., at Horse Gully (UNEL1761). The steinkern has a well-pre-· served specimen of Endoconchia lata sp. novo attached to it (Fig.10F,G).
Subphylum DIASOMA Runnecgar. &Pojeta, 1974 Class BIVALVIA Linnaeus,1758 Subclass PALAEOTAXODONTA Newell, 1965 Order NUCULOIDA Dall,1889 Family PRAENUCULIDAE McAlester,1969 "\
,.
Pojetaia Jell, 1980 Type species. Pojetaia runnegari Jell,1980, Early· Cambrian, South. Australia; by original . designation. Diagnosis. Tiny, subequilateral, equivalved �ivalve with one to three simple cardinal teeth in each valve and a sunken, opisthodetic, pari vincular ligament mounted on the thickened edges of the valves.
EARLY CAMBRIAN FOSSILS, S. AUST.
Posterior adductor muscle scar sizeable, anterior adductor muscle scar small; pallial muscles at tached at a series of discrete, comarginal sites. Shell apparently originally aragonitic, composed of a single layer of composite sub units that produce a characteristic set of imbricated polygons on internal moulds. Valves smooth ex ternally except for a few obscure radial ridges in the lunular areas; larval shell not clearly separate from adult shell.
257
what similar planispiral microfossils have been described from the Middle Cambrian of Sardinia as e a r l y f o r a m i n i f e r a n s Schroeder,1985).
(Ch e r c h i
&
A rdrossania paveyi Runnegar sp. novo (Fig. 173A-D,G-L)
Efymology. For Mr Alan Pavey, owner of the property that contains Horse Gully.
Remarks. Oryzoconcha He & Pei,1985 occurs with Pojetaia in China and is indistinguishable from it.
Material. H o l o t y p e S A MP 2 9 0 2 8 , f r o m UNEL1761, Parara Lst., Horse Gully; C . 2 00ther specimens from the same locality.
Pojetaia runnegari Jell,1980 (Figs 165,166)
Description. Evolute, planispiral coils c. lmm in diameter. Most are relatively featureless but the holotype displays a number of additional charac ters. These include a shallow groove on the periphery ofthe last whorl (Fig.173A,D, G,J) and a wall structure that seems to have been formed by symmetrically disposed, tangential crystal lites. Enlargement of the edge of the shell shows it to consist of two thin phosphatic layers held apart by vertical walls (Fig.173H,I,L). The space between these walls appears to have been oc cupied by fibrous crystals of much the same d i m e n s i o n s as t h o s e fo u n d i n Pelagiella (Fig.173E,F). Thus it seems as if the shell of A. paveyi was originally formed of calcium car bonate, probably aragonite.
1980 1983 1985 1985 1985
Pojetaia runnegari Jell, p.234. Pojetaia runnegari Jell; Runnegar & Bentley, p.74. Pojetaia runnegari Jell; He & Pei, p.63. Oryzoconcha prisca He & Pei, p.64. Pojetaia ovata Chen & Wang, p.28.
Material. Hundreds of phosphatic internal moulds and some phosphate coats from the Parara Lst., Ajax Lst. and Oraparinna Shale (UNEL1760-2, 1763c, 1764, 1766c, 1778, 1833, 1853-4,1856, 1860, 1860a-b, 1872-4,1877).
Description. The species is fully described in Jell (1980) and Runnegar & Bentley (1983). Remarks. The Chinese specimens of P. runne gari lie within the range of variation of the species at its type locality and are approximately equivalent in age. PROBLEMATlCA
Discussion. Affinities of A. paveyi remain uncer tain. [n terms of its shell construction, A rdros sania shows some similarities to the pelagiellid gastropods' (Fig. 170), but t h e r e are also s i m i l a r i t i e s t o the ultradextral gastropod Yuwenia (Fig.171) and also, perhaps, to hyoliths (Runnegar et aI., 1975).
Ardrossania Runnegar, gen. novo Etymology. For the town of Ardrossan, Yorke Peninsula, South Australia. Type species. A rdrossania paveyi sp. novo Diagnosis. Microscopic, planispiral, evolute, phosphatic fossil, with a circular whorl cross section. A shallow groove that lies in the plane of symmetry of the shell is present on outerwhorl surface ; the shell wall appears to have been fibrous and may have been carbonate rather than phosphatic. Remarks. These tiny planispiral shells superfi cially resemble some younger and much larger molluscs, but there is no clear evidence that they were fonned by member of that phylum. Some-
TRILOBITA
[PAl]
In the descriptions that follow all dimensions in the sagittal or exsagittal direction are expressed in terms of length (i.e. long and short) whereas all those in the transverse direction are in terms of breadth (wide and narrow) regardless of which is the greater dimension. For example the length of thoracic pleural furrows in my terms would have been the width of the furrow in most pre vious authors' terms. Glabellar furrows are referred to as SO (occipi tal), SI (first lateral glabellar), S2, S3 etc. and glabellar lobes so defined are referred to as LO (occipital), Ll, L2, L3 etc. towards the glabellar anterior following Henningsmoen (1957). The series of Greek letters indicating significant
258
STEFAN BENGTSON
et
al.
points on the facial sutures follows the terminol ogy of Richter & Richter (1940, fig. 3D).
t e r p r etat io n o n new material (Re p i n a & Pereladov, 1988) show it to be an eodiscid), and Dicerodiscus Zhang W.T., 1964 all Early Cam Order MIOMERA brian derivatives from 'separate sighted ancesSuperfamily EODISCOIDEA . t o r s. Yukonides p r o b a b l y e v o l v e d o u t of Korobovia gen. nov. whereas Lenadiscus is so distinctive that its origins are unknown but cer The aim of studying the taxonomy of any group of organisms is to understand their evolutionary tainly distinct from Yukonides; Dicerodiscus ap history; the secondary aim of establishing a clas pears to have affinities with the Neocobboldia ' lineage although this is not certain. The grouping sification, a set of pigeon-holes into which all into one family of forms having eyes or eye members may be placed, is merely a matter of convenience for ease of recognition and ease of tubercles but no facial sutures pays no attention referring to that group. When the classification to evolutionary lineages and must be abandoned. Similarly family or higher level groupings based becomes more important than the evolutionary pathways. an artificial, usually quite misleading, on presence or absence of eyes are inappropriate. classification having little evolutionary sig As further discussed below a greater number nificance may result. In 1975 I demonstrated that of lineages evolving to blindness are now known earlier' classifications of the Eodiscoidea were and it appears that the glabella is the most impor artificial because they had been based on a tant part of the exoskeleton in identifying mem bers of a lineage although variations in other single, easily observed character change, which had been assumed to have occurred only once in features such as the borders, preglabeUar area the history of the superfamily. Since 1975, two and pygidial axis taken in various combinations are also indicative of different lineages. I suggest major works on eodiscoids have appeared by Korobov (1980) and by Zhang S.G. (in Zhang that the presence or absence of eyes should be W.T. et al., 1980); each ignored the major con used as a specific character only, if all other features correspond. clusion of my 1975 paper - that evolution to blindne,ss occurred along several lineages within the superfamily - Or chose to continue employ Family WEYMOUTHIIDAE Kobayashi,1943 ing the easily recognized 'blind' or 'sighted' distinction at family level.. With the relatively Serrodiscus Richter, R. & Richter, E.,1941 small number of lineages known before 1975 the 'artificial' classification was workable up to a Type species. Eoqiscus (Serrodiscus) serratus Richter, R. & Richter, E.,1941 from the Early point but the increase in diversity of morphologi Cambrian of Spain; by original designation. cal forms since then has made the family level division based on blindness totally inappropriate. With the array of morphologies revealed by Remarks. The concept of Serrodis.�us outlined by Kot-obov (1980) in the Mongolian eodiscoids it Rasetti (1952) and reiterated by Opik (1975b) is is clear that more than three eodiscoid lineages accepted herein. Serrodiscus gravestocki sp. nov. has the critical pygidial marginal spines and evolved to blindness and in some cases it now seems appropriate to include blind and sighted typical cephalic border tubercles of Serrodiscus forms in the same genus. For example cephala of but it has a deeply transversely divided and Mongolodiscus zaicevi Korobov (1980, p1.9, figs posteriorly inflated glabella not seen in that 1,2) are so similar to Egyngolia obtusa Korobov genus. The glabella is similar to that found in the (1980, p1.7, figs 1-10) in every respect except the s e v e r a 1 s p e c i e s a s s i g n e d t o Meniscuchus possession of eyes that they must be considered Q pik,1975b. It is also to be found in S. daedalus congeneric. The lateral glabellar furrows, pitOpik,1975b which, incidentally, does not have like and isolated from the axial furrow, are parpygidial border spines. It seems reasonable then ticularly distinctive of this lineage. To suggest, tQ infer that S. gravestocki and S. daedalus rep as Korobov (1980) has done that these species resent a lineage that began early in the history of belong to separate families based on one feature Serrodiscus and involved shortening and defin alone shows the inappropriateness of the older ing L3 and loss of pygidial border spines. If this approach. Similarly Zhang S.G. (in Zhang W.T. " distinctive glabellar segm�ntation evolved only et al., 1980, fig. 7) has grouped into the Opsidisonce then Menischuchus Opik, 1975b should be cidae Opsidiscus Westergard, 1949 from the late 'considered a derivative from Serrodiscus rather Middle Cambrian and a member of the Pagetia than Calodiscus (Geyer, 1988). It should be noted that at least one specimen of Hebediscus lineage with Yukonia Palmer, 1968 Yukonides (H. attleborensis S ha l e r & Fo e r s t e , sensu Fritz,1972, Lenadiscus Repina in Khomentovsky & Repina, 1965 (based on a pygidium then Lazarenko,1964, p1.2, fig 17) shows the short L3. Ninadiscus K orobov, 1980 with its type N. interpreted as a cranidiutn but correction of in-
EARLY CAMBRIAN FOSSILS. S. AUST.
strobulatus Korobov,I 980 from late Aldanian of western Mongolia and N. walcotti (Rasetti, 1952) from the Lower Cambrian of New York has the same glabellar structure but its relation ships may only be achieved when the structure of its pygidial border is available. If it lacks spines it may well prove to be a synonym of Meniscuchus. In 1975 in my review of this superfamily I used New Genus I for a species being described by A. A. Opik; that notation was based on the sm�cies now known as S(!rrodiscus daedalus Opik, 1975b. I considered it to represent a separate genus because of its quite distinct glabella among species of Serrodiscus known at that time and because it lacked pygidial border spines. However, discovery of S. gravestocki with the same type of glabella and cephalic border but with a pygidial border typical of Serrodiscus shows that separate generic status is not war ranted because S. daedalus simply represents part of the lineage within Serrodiscus that may have led to M enischuchus. The taxon that I rep re _ sented Opik (1975b) as Meniscuchus. The grouping of S. daedalus with Ladadiscus Pokrovskaya ,1959 (Jell,1975, fig.5) in cluster analysis of 40 mor phological features reflects the distinction of these two taxa in lacking pygidial border spines while having typically Serrodiscus features in most other characters. Ladadiscus has a glabella typical of Serrodiscus so it is unlikely to have evolved through the same lineage as S. daedalus; I think it most likely that Ladadiscus represents a later lineage from Serrodiscus involving the same loss of pygidial border spines. Serrodiscusgravestocki Jell, sp. novo (Fig. 175) Etymology. For Or Oavid Gravestock, South Australian Geological Survey, for his contribu tion to Cambrian studies in the Flinders Ranges. MateriaL Holotype NMVP112801; paratypes NMVP 112778, 112779, 112780-112782, 112786-112789, 112791, 112792, 11279 5, 112796, 11279 9, 112800, 112801, 112805, 112810, 112812, 112814-112816, 1270 48, 127049 from NMVPLl589, Bunyeroo Creek, Orapa rin n a Shale. Other material NMVP1I 2719, 112726, 11272 9 , 112736, 112740, 112748andl13153 from NMVPLl588, Bunyeroo Creek, Oraparinna Sh a l e ; NMVP 1I1882, 113222 from NMVPLl590, Bu n y e r o o Creek, Oraparinna Sh a l e ; NMVP 1270 39- 127041 from NMVPLl5 99, west ofWirrealpa Spring, Oraparinna Shale. Diagnosis. Member of Serrodiscus with glabella
259
distinctly divided by continuous well-impressed S2 and S3; posterior lobe (i.e. LI+L2) longest, greatly expanded but not spinose posteriorly and extending back overoccipital ring; L3 very short and transverse; frontal lobe slightly expanded; anterior border prominent, with seven pairs of tubercles decreasing in size anteriorly, slightly elongate anteromedially. Pygidial axis of 8-9 rings, tapering strongly posteriorly, bearing low blunt tubercles on anterior rings; border narrow, bearing 8-9 pairs of ventrally directed spines that give the effect of a scalloped skirt; pleural areas smooth or rarely with barest expression of seg mentation. Description. Cephalon just wider than long, rising posteriorly in lateral profile. Glabella ex tending almost to anterior border furrow from which it is separated by very short depressed preglabellar field, gently tapering forward to posterior of frontal lobe, frontal lobe bluntly sub angular anteriorly; posterior of glabella (i.e. L1+L2) inflated posteriorly; SI as pits near the axial furrow at the midlength of the inflation; S2 and S3 continuous, transverse, well-impressed with S3 deeper than S2; LI to L3 each occupying 0.2 and frontal lobe occupying 0.4 of glabellar length; frontal lobe wider and more inflated than L3; SO posteriorly convex, running around posterior low on glabellar inflation, finishing laterally just short of axial furrow; LO short, low at rear of glabella. Fixigena narrow, high as frontal glabellar lobe. Border furrow deep and long anteromedially, shallow and narrow lateral ly, then deep and long again posteriorly where it runs diagonally from posterior margin behind lateral extremity of occipital ring forward at acute angle to posterior margin to meet lateral border furrow, but then continue directly to lateral margin. Border with seven pairs of sym metrically placed tubercles decreasing in height anterioriy, with tubercles set on crest of border near border furrow, with slope from crest to margin relatively gentle anteriorly becoming steeper lateral1y so that in dorsal view border is narrowest laterally; posterior border short, con vex, longest and most prominent at lateral articulation then steeply downsloping laterally with flat articulating facet cutting off posterior corner. Pygidium just wider than long. Axis of total width at anterior, tapering posteriorly to rounded end near but above border furrow , of eight rings and a terminus; second ring longest, best defined by ring furrows and bearing highest tubercle; impression of ring furrows, length of rings, development of dorsal spine and height all decreasing posteriorly until last ring and ter minus are low, poorly defined, and nontubercu-
in
260
STEFAN BENGTSDN et al.
Fig. 175. Serrodiscus gravestocki Jell, sp. novo A, cephalon NMVPl12736. B,C, dorsal and anterior oblique views respectively, of cephalon NMVPl12801. D, cephalon NMVP127039. E, right·lateral view of cephalon NMVP112726. F,G, dorsal and right lateral views, respectively, of pygidium NMVPl12719. H, left oblique view of pygidium NMVPll1882. I, right lateral view of pygidium NMVP127049. J, right lateral view of pygidium NMVP I I 2740a. K, ccphallln NMVP 12704'0. L, cephalon NMVP 11277'0. M, pygidium NMVP113222. N,D, posterior oblique and dorsal views respectively of pygidium NMVPI12729. All xl0, except H, x7, J, x1S, and M, x7.
EARLY CAMBRIAN FOSSILS,
late; anterior axial ring as long as fourth but almost as high and tuberculate as second. Pleural area smooth or with faint ridges (probably inter plueral) running transversely to border just be hind e a ch b or d e r s p i n e . Bor d e r f u r r o w well-impressed on steep lateral slope that be comes vertical at posterior so that furrow is bare ly visible in dorsal view; anterior border furrow well-impressed, running at acute a ngle to anterior margin behind prominent articulating point and steep articulating facet. Border narrow, tapering posteriorly, sloping laterally and with seven pairs of centrally and slightly laterally directed br o a d spines decreasing in s i ze posteriorly (spines short and broa<;l giving scal loped appearance in lateral view.
1972 1974' 1980
0
Discussion. Variation in this species may be due to preservation in different lithologies at dif ferent horizons. Impression of glabellar furrows, particularly SI and S2 is variable as is the length of the frontal lobe and consequent forward extent of fixigena. The latter is never very great. Infla tion of the glabellar rear is variable and in a few specim�ns the border appears elongate and ' weakly inflated in sagittal line. This species is distinguished by its long, posteriorly inflated and deeply furrowed glabella,its narrow pygidial axis, and spinose pygidia] margin; within Serrodiscus its glabellar features are distinctive. Most closely related is S. daedalus as discussed above, but the greatly inflated glabella,9-segmented pygidial axis and narrow spinose border are distinctive in S. gravestocki. This species was identified by Jenkins (1990, ..p. 413) as Calodiscus (Serrodiscus) daedalus Opik,and indicated on the section (Jenkins, 1 990, fig.9) as Calodiscus. Generic attribution is discussed above and any suggestion of assignment to Calodiscus or reduction of Serrodiscus to subgeneric status, without due discussion and justification does not bear further consideration. I have been unable to find any specimen to verify Jenkins's (1990, pA13) record of Meniscuchus in this fauna,in any of the material kindly sent to me by Jim Jago as representing the material from which Jenkins's identifications were made or in my own extensive collections from the site at the western end of Bunyeroo Gorge. During growth the cephalic border tubercles become more obvious and larger, the frontal glabellar lobe expands more than L3 and the glabellar rear becomes relatively less inflated.
.
261
.
Lu etaL, p. 84. Y�o; Zhang S.n.in
Szechuanaspis Chien & Yao in Szechuanaspis Chien &
W.T. etal.; p. 33.
0
0
Margodiscus Korobov, p. 54. [partim.]
Diagnosis. Eodiscid with subcyIinrlrical glabella bearing virtually no furrows,with short occipital spine,with long preglabelIar length,usually with preglabeUar median pit,withshort,convex,often poorly defined border,with eye -lines transverse often prominent on internal moulds,with well impressed palpebral furrows, with convex pal pebral lobes often longer than librigenae,facial suture proparian. Pygidium convex, with rela tively narrow axis of 5-7 segments lacking ter m i na l s p i ne , a n t e r i o r s e g m e n t s u s u a ll y tuberculate,with pleural areas varying from well furrowed to smooth,with narrow border bearing small marginal spines, at least in anterior part, that are situated at posterior of segments where pleural segmentation is evident.
0
Hebediscina Rasetti, 1972
.
Type species. Hebediscina sardoa Rasetti,1 972 from the Lower Cambrhin Nebida Formation of Sardinia; by original designation.
0
Family EODISCIDAE Raymond, 1913
AUST
Hebediscina Rasetti, p.46.
Zhang
1980
S.
.
Discussion. Rasetti ( 1 972) disti.nguished Hebe discina from Hebediscus, Pagetides, NeocoQbo! dia, and Pagetia. Since then two major works have described synonymous genera. Margodis cus Korobov,1980 was erected with M: rack ovskii Korobov,1980 as type species. However, M. rackovskii, whose holotype is a small cranidium (Korobov,' cranidia indistinguishable, indeed conspecific with those of Neocobboldia quadrata Korobov, 1980 (p1.5,figs 13,1 4) and pygidia that are con specific with those of Margodiscus porrectus Korobov,1980 which occur in the same horizons (Korobov,1980). Therefore, the species rack ovskii is assigned to Neocobboldia and based on page priority is considered a senior subjective synonym of Neocobboldia quadrata. Among other species that Korobov (1980) assigned to Margodiscus, some are referable to Hebediscina based on the long preglabellar area, prominent palpebral lobes,narrow pygidial axis of 5-:7 seg ments and spinose pygidial margin. Szechuanaspis Chien & Yao inLu et ai., 1974) from southwestern China generally lacks pygidial pleural furrows and may have an in cipient occipital furrow but otherwise it is iden tical with Hebediscina, which similarity was recognized by Zhang S.G. (in Zhang W.T. et ai., 01980). ThcS9 features arc not considered to be of ge neri c significance and subjective synonymy is indicated herein despite the discussion of Zhang S.G. (in Zhang W.T. et ai., 1980). Hebediscina 0
'
0
.
0
0
0
.0
262
STEFAN BENGTSON et al.
Fig. 176. Hebediscina yuqingensis Zhang S.G. in Zhang W.T. et al.,1980. A,B, anterior oblique and dorsal views, respectively of cephalon NMVP112745. C,D, left anterior oblique and dorsal views of cephalon NMVPI12725. E, right oblique view of pygidium NMVPI12728. F, cephalon NMVP 112840. G, pygidium NMVP112840. H, cephalon NMVP112758. I, cephalon NMVP112722. J,K pygidia NMVP112740 and 112730. All x15, except E,G, x12.
sardoa and Szechuanaspis yuqingensis may be synonymous which would give a correlation of the lower Tsanglangpu Stage in China with the P. janeae Zone in Australia and the Maloppa Member of the Nebida Formation in Sardinia (Rasetti, 1972). Hebediscina yuqingensis (S.G. Zhang in W.T. Zhang et al.,1980) (Fig.176) 1980 Szechuanaspis yuqingensis Zhang S.G. in ZhangW.T. et al., p.35.
Material. Holotype NIGP37315 (W.T. Zhang et al. ,1980, p1.3, fig.2); paratypes NIGP3731637321 (W.T. Zhang et al.,1980, p1.3, figs 3-8). Australian material NMVPl12714, 112725, 112735, 112745, 112758 (cranidia) NMVP 112728, 112730, 112737 (pygi d ia) from NMVPL1588, Bunyeroo Creek, Oraparinna Shale; NMVPl12840 from NMVPL80, Buny eroo Creek, Oraparinna Shale.
D iagnosis. Member of Hebediscina with short preglabellar field; with relatively narrow glabel la having slight constriction behind frontal lobe in all but most m ature specimens, broadly rounded to truncate anterior and virtually no furrows; relatively small, prominent, palpebral lobe down side of high fixed cheek. Pygidium with 7 axial rings, 5 pairs of marginal spines and faint pleural furrows. Description. Cranidium just wider than long, weakly convex, with posterior of glabella high above fixigenae in anterior profile and a l ateral profile that rises steeply up the glabella after a dip into the border furrow. Glabella with straight parallel sides, faintly expanded in frontal lobe, with bluntly rounded to truncated anterior, with only the vaguest depressions beside the axial furrow in the base of the glabella to represent glabellar furrows; SO represented only by pair of steeply sloping pits low on sides of glabella; posterior of glabella and occipital ring drawn out
EARLY CAMBRIAN FOSSILS, S. AUST.
posterodorsal1y into strong pointed projection. Preglabellar field lowest point between rise on each fixigena but not depressed as its base is higher than border. furrow, as long as border (sag.); border furrow well-impressed, tapering and shallowing la terC;llly; border el ongate medially, convex in section but narrow and downsloping at facial suture. Eye line runs from glabella at rear of frontal lobe in anteriorly con vex arch to anterior of palpebral lobe which is defined by sharp exsagittal palpebral furrow and situated low on side of fixigenal peak. Librigena small, situated anteriorly at level of first segment behind frontal lobe. Posterior border furrow leaving posterior marginjust behind axial· furrow and running forward at an acute angle to margin, deepening and becoming elongate laterally before shallowing and narrowing as the lateral border furrow; posterior border with prominent lateral articulating point and steep flat facet beyond. Pygidiumjust slightly wider than long, strong ly convex with axis standing high above rest, with second and third rings of axis highest part in lateral profile. Axis of seven rings and Short posteriorly rounded terminus finishing just for ward of posterior border furrow, with anterior five rings bearing relatively high tubercles and well defined by sharp transaxial furrows, with three posterior segments lower and less distinct. Pleural areas convex, with poorly impressed pleural furrows becoming less distinct and more exsagittal to posterior; border furrow poorly im pressed and more or less on steep slope of pleural areas; border sloping laterally, widest near mid length of pygidium, with five pairs of small blunt marginal spines at positions lateral to rear of first five pygidial segments. Articulating facet steep, convex, cutting off anterolateral corner. Remarks. There seems to be little variation in this species although the impression of glabellar, axial and pygidial pleural furrows as weB as development of the pygidial marginal spines do seem variable to small degree. The librigenal area apparently becomes longer and the pre glabellar field becomes longer and depressed separating the fixigenae with growth (cf. smal1 Australian specimens with larger Australian and Chinese specimens) .. The Australian material exhibits external sur faces whereas the· Chinese specimens are ap parently intemal.moulds so there are some minor differences but not such as to separate specifical ly. It is important to make the comparison on specimens of comparable size (i.e. taking Fig. 176H,I as adults for comparison). The anterior border, occipital spine, palpebral furrow, pygidial marginal spines, and furrowed
263
pleurae are similarities with H. iongispinus Chien & Yao in Lu et al., 1974 but distinctions include anterior glabelhu shape, length of preglabellar field, size of palpebral lobe, number. of pygidi(!l axial segments and size of marginal spines. Other species are generally different iated by wider glabella and shorter occipital spine. The anterior glabellar,shape resembles'H. planus Zhang S.G. in Zhang W.T. et al.,1980 (pl.3, fig.12) which might be considered synonymous. if the pygidial assignment to that species proves incorrect. H. sardoa may prove to be senior synonym of yuqingensis but for the moment its shorter anterior border, longer preglabellar field, and better segmented pygidium with more prominent . marginal spines serve to separate the species� Thi s species was incorrectly assigned to Page tides by Jenki n s (1990, p. 413) . The pygidial marginal spines being sufficient to dis.. tinguish the genera.
Korobovia Jell, gen. novo Etymology. For the lateM. N. Korobov, Soviet palaeontologist. Type species. Korobovia ocellata gen. et sp. nov.. Diagnosis. Eodiscoid with' straight, parallel to slightly tapering glabellar sides. Glabella which is poorly divided by transverse furrow 1/3 of length from. anterior, with well-impressed oc� cipital furrow, with occipital ring drawn out posteriorly to blunt point or short fine spine. Eye line convex forward. Eyes or eye tubercles situated well forward and closer to height of border furrow than peak of fixigena. Palpebral lobe and librigena both very small. Border short, uniform and thread-like. Pygidium with relative ly broad axis of four rings plus terminus standing above pleural areas and at least first ring tuber culate. Pleural fields with pleural furrows. Bor der narrow, low, with or without marginal spines. Remarks. This genus may have arisen from Hebediscina through Margodiscus blagonravovi Korobov,1980 or a very similar speCies; glabel lar shape, long depressed area forward of the g]abel1a and fixigenae not extending in front of glabella, well-imp ressed occipital furrow, pygidial axis of five segments with· high tubercles on anterior ones and spinose border all relate that species to Korobovia where it is now placed. Neopagetina conica Korobov, 1980 from the Le n i an Ya r u s o f western Mong olia and Neopagetina infirma Egorova in Khalfin, 1960 and N. fusa E. Romanenko in E. & M. Rom-
264
STEFAN BENGTSON et al.
Fig. 177. Korobovia ocellata Jell, gen. et sp. novo A., cephalon NMVPl12664. B, cephalon NMVPl12690. C,F, anterior and dorsal views of holotype cephalon NMVP112656. D, cephalon NMVPl12661. E, cephalon NMVPl12675. G, left lateral view ofcephalon NMVPl12671. H, right lateral view ofpygidium NMVPl12691. I, right lateral view of pygidium NMVPl12666. J, pygidium NMVPl12678. K, pygidium NMVP 112655. L, pygidium NMVP112654. All xIS.
anenko, 1967 from the R. Katun Basin in Gorny Korobovia ocellata Jell, sp. novo (Fig.I77) Altay from the Botomian and Lenian (Repina & Romanenko, 1978) exhibit cran idial features Etymology. Latin ocellus, the diminutive of similar to those of Korobovia and probably oculus, eye. belong to that genus. Yukonides Fritz, 1972 from the Nevadella Material. Holotype cranidium NMVPI126.56; Zone of northwestern Canada �md the Siberian paratypes NMVP112653, 112664, 112666, species of Lazarenko (1964, pl.1, figs 8-13; in 112678, 1126 91 (cranid ia) NMVP112654, Datsenko et al., 1968, p1.20, figs 7-14) are dis 112655, 112661, 112671, 112675, 112682, tinguished by the reduction of the eye having 112690 (pygidia) all from NMVPL87, west of proceeded to the stage where only a marginal Wirrealpa, Oraparinna Shale. tubercle remains. Tcheryshevioides ninae Haj rullina (in Repina et al., 1975, pI. 7, p1.8, figs Diagnosis. Member of Korobovia with distinct 1-6) from the Amga Stage of Turkestan is super proparian facial suture and palpebral lobe; oc ficially similar in the stage of eye reduction but cipital ring drawn out to blunt projection not a its glabella, border, occipital and genal spines, . spine. Pygidial border with three pairs of blunt and pygidial segmentation separate that genus. spines anteriorly. Yukonia Palmer, 1968 from the Early Cambrian of Alaska has small eye tubercles in the same Description. Cr a n i d i u m wid er t h a n long, position as the palpebral lobes in Korobovia but domi nated by highly convex fixigenae and glabella, with entire surface bearing ornament of it has no librigena, less distinct occipital furrow, extremely narrow pygidial axis, and long occipi extremely fine reticulate ridges giving punctate tal spine. appearance. Glabella just over 1/2 cranidial
EARLY CAMBRIAN FOSSILS, S. AUST.
265
length, with straight parallel sides and narrowly anterior corners. Glabella wide, subcylindrical to rounded anterior, with low frontal lobe occupy subconical with obtuse anterior end, raised above ing 1/3 glabellar length (Le. without occipital fixed cheeks; two pairs of well-defined lateral ring) and defined by long shallow S2, with highly furrows. Axial furrow wide, deep, sometimes convex posterior lobe highest towards the rear with a tubercle on each side near the base. Oc and bearing indistinct SI low on its side near cipital furrow shallow. Occipital ring drawn out into spine. Frontal limb of variable length. Fixed midlength. Occipital ring isolated by long, well impressed, laterally shallowing occipital furrow, cheek convex, of variable width. Palpebral lobe elongate posteromedially into blunt pointed small, situated in anter-ior half of cranidium or projection continuing laterally as low ridge into near to middle. Eye line long, thread-like. posteroproximal corner of fixigena. Preglabellar Ant erior border f urrow shallow, n arrow. field short, only weakly depressed in front of Anterior border narrow, in form of a line, well glabella. Anterior border furrow long, moderate defined or indistinct. Posterior border furrow ly deep, of uniform length throughout. Anterior shallow, narrow. Posterior border narrow. Facial suture of pagetioid type. Thorax of three seg� border short, with convex sectiQn especially approaching anterior margin. Eye line leaving ments. Pygidium transverse, with well-defined segmentation. Axis of six or seven rings with glabella at posterior of frontal lobe, curving for ward over fixigena to short palpebral lobe. Eye tubercles, strongly tapering to rear, finishing a situated well forward at level of anterior of short distance from border furrow. Border and glabella, low on side of fixigenal elevation well furrow narrow. Cranidium and pygidium with small tubercles or without. away from highest point; palpebral lobe short, wide, defined by distinct palpebral furrow run Remarks. Korobov (1980, p.84) likened this ning into border furrow posteriorly. Librigena extremely small, subrectangular. Fixigena genus to Neopagetina Pokrovskaya,1960 (=Pag elides) of the Pagetiidae with the parallel sides of strongly convex with highest point level with the glabella, distinctive glabellar furrows, wider middle of posterior glabellar lobe, with lateral eyeline and transverse pygiditim generically dis..; slope almost vertical but rise from. axial furrow much gentler. Posterior border furrow well-im- . tinctive. The anteriorly truncate glabella 'with parallel sides and the style of lateral glabellar pressed, straight, running forward from posterior furrows are probably the most distinctive fea margin at outer edge of axial furrow at acute tures but the latter appears not to be shared by the angle to margin and isolating relatively large triangUlar posterolateral border area. second Mongolian species E.. bella Kotobov, Pygidium markedly convex, tapering gently 1980 which is doubtfully retained in the genus. posteriorly, length 0.7 of width. Axis occupying Further members of Egyngolia were erected by C. 0.3 of width, of four rings bearing long spines Repina (1972, p1.30, figs 4--10) as Calodiscus and short posterior nonspinose terminus finish . resimusfrom the Golovnoy Suite along the River Sukharikha on the Siberian Platform in sedi ing forward of border furrow. Pleural areas nar row with shallow pleural furrows becoming less ments of the Taryn Gorizont and by Repina (in Belyaeva et aI., 1975, p1.39, figs 1-10) as distinct posteriorly. Border furrow not impressed but represented by change in slope to flatter Neopagetina dzagdinica from the· Gerbikansk border; border widening posteriorly, with three Gorizont on the River Gerbikan in the Far East (contemporary ofTaryn Gorizont); the anteriorly pairs of broad blunt marginal spines. Articulating truncated glabella, pit in the preglabellar furrow, facet di,stinct, SI isolated from the axial furrow, small anterior ltemarks. This species may be distinguished by ly placed free cheeks, 7-segmented pygidial axis and tubercles on the pygidial margin attest to this its facial suture and distinct palpebral lobe. It placement. The same features are evident on E. may be separated from its probable ancestor H. dzagdinica (Repina in Belyaeva et aI., 1975) blagonravovi by its much smaller librigena, by from the Early Cambrian Gerbikansk Gorizont its' divided glabel1a, lack of preglabellar pit and ( = Taryn Gorizont) in the Soviet Far East. Mon pygidial axial spines on four segments. golodiscus Korobov, 1980 with type M. zaicevi Egyngolia Korobov,1980 Korobov,1980 based on two cranidia exhibits the lateral glabellar furrows isolated from axial fur row, truncated glabella, long preglabellar length, Type species. Egyngolia obtusa Korobov,1980 thread-like border and remnants of eye lines that from the Atdabanian Egyyngolskaya Suite in northwestern Mongolia; by original designation. place it in Egyngolia; the lack of eyes is not considered generically significant as evolution to blindcss is common in this group and this is but Diagnosis. (Translated by P.A. Jell) Cranidium flatly convex, sub rectangular with r ounded the end member of one such lineage from Egyn-
266
STEFAN BENGTSON
et
al.
Fig. 178. Egyngolia willochra Jell, sp. novo A-G, cephaJa NMVPl11849 , 111868, 111853, 111848, 111860, 111860, 111871. F, anterior oblique view of E. H-K, pygidia NMVP111865, 111852, 1 11864, 111869. All x12,exceptA, xl0
golia. I consider Mongolodiscus a junior subjec tive synonym of Egyngolia. The origin of Egyngolia is not certain but it appears most likely to belong to the Hebediscus lineage possibly deriving from a form like H. ponderosus Lermontova,19 51 which had the broad glabella with blunt anterior, short anterior border, short occipital extension and tuberculate pygidial axis and border. Egyngolia willochra Jell, sp. novo (Fig.178) Etymology. Name of the nearby creek - a noun in apposition. Material. Holotype NMVPll1860; para types NMVPl11 848, 111849, 111852, 11185 3, 111861, 111863-111865, 111867-111869, 111871from NMVPL1585, north of Mt Ragless, Parara Lst. Diagnosis. Member of Egyngolia with a shallow pit medially at the anterior of the glabella, with
slight elongation of the anterior border in the sagittal line, with a pygidial axis of six rings and a short terminus, with indistinct pleural furrows on some but not all pygidia and with prominent marginal tubercles on lateral pygidial border. Description. Cranidium just longer (without oc cipital spine ) than half width. Glabella occupy ing 0.7 of cranidial length, with straight parallel sides and truncated anterior; two pairs of lateral glabellar furrows well-impressed, with S2 pit like although extending slightly anterolaterally to reach axial furrow; SI a circular pit isolated from axial furrow; S2 continuing shallowly across axis in immature individuals. Occipital furrow impressed laterally only as large, slightly elongate pit isolated from axial furrow. Occipital ring short, curved posteriorly and extended posteromedially into strong spine. Axial furrow wide and tapering forward; preglabellar furrow short, wide, with distinct median pit; baccula situated at posteroaxial corner of fixigena, dis tinct in small specimens becoming quite indis-
267
EARLY CAMBRIAN FOSSILS, S. AUST.
/
tinct in larger ones. Anterior border furrow usual l y l o ng (re la tively shorter i n small specimens), elongate ppsterorriedially in many' specimens, shallow. Anterior' border smooth, with posteromedial elongation. Fix:igena narrow (each only slightly wider than glabella), convex with gentler slope from axial furrow and steep '. almost vertical lateral slope; distinct but low eye line running from anterolateral corner of glabella in anteriorly convex curve across fixigena and then back just above border furrow to small eye. Librigena and eye small, situated at level of L2; facial su!ure proparian, diverging little from anterior and posterior ends of eye; librigenal border and border furrow extremely narrow; bor der furrow widening to posterolaterCJ,1 corner from rear of librigena. Posterior border furrow short at adaxial end at posterior margin behind occipital ring, becoming elongate and, running obliquely forward laterally; geniculation point and small indistinct posterolateral facet evident. Cranidial surface smooth. Hypostome and thorax unknown. Pygidium sub�semicircular, of low convexity; gently tapering axis of six rings and extremely short terminus separated from posterior border furrow by no more than its own length; each ring with median tubercle; ring furrows straight and well impressed. Pleural areas crossed by ex tremely faint pleural furrows and Tines of pus tules on pleural bands. Border furrow distinct, widest near pygidial midlength' and anteriorly behind steep flat articulating facet. Border taper ing to sagitta] line and to anterolateral corner, bearing six pairs of fine posterolaterally directed tubercles evenly spaced laterally and probably representing pleural tips of the pygidial seg ments. Remarks. Available material is preserved in crys talline limestone that does not lend itself to preparation' of such small exoskeletons so the material is either not fully prepared or unavoid ably damaged during preparation. However, enough specimens are available to be confident of the morphology described and the generic assignment. Egyngolia willochra differs from the type species in the elongate anterior cephalic border, and on the pygidium the short axial terminus, faint pleural furrows and tubercles on the border. E. willochra is presumably the species from the area of this locality mentioned by Daily (1 956, p.111) as 'similar to Pagetia but combining fea tures which recall both Dipharus and Calodis cus.' . Order REDLICHIIDA Family REDLICHIIDAE Poulsen,1927
Redlichia Cossmann,1902
Type species. Hoeferia noetlingi Redlich, 1899 from the late Early Cambrian of the Salt Range in Pakistan; by original designation. Redlichia guizhouensis Zhou in Lu et al., 1974 (Fig.179) 1919 Olenellus (?rsp. Etheridge" p1.39, fig�L 1974 Redlichia guizhouensis Zhou in Lu et aI., p.8S, ' p1.31, fig.l0. 1978 Redlichia (Redlichia) guizhouensis Zhou; Zhou in Yin & Li, p.400, pI. 147, fig.1. 1981 Redlichia guizhouensis Zhou; Lu, pt.l, fig.20. '
Material. Holotype NIGP21473 (Zhouin Zhang et al., 1974, p1.31, fig.l0). AU'stralian material NMVP112889, 112892, 112896, 112898112901, 112903, 11290 5, 112907; 112908, 112911 , 112 912 and 112 9 1 4 . Ail f r o m NMVPL88, northwest ofWirrealpa, Wirrealpa Lst. · Diagnosis. Species ·of Redlichia si�ilarto R. chinensisWa1cott,1913 except that width acr()ss anterior part of cranidiuni (i.e�f3�f3) is 1.1 times cephalic length and the pygidiuin-has �oneaxial ring in front of bilobed terminus that slopes gent ly to posterior for some' distance and ,has an unexcavated posterior margin. .' ,
'
Description. Cranidium gently convex, with fixed cheeks below glabella in anterior profile. Glabella covered with fingerprint-like terrace lines, weakly convex, with straight sides con verging slightly forward to rounded anterior just behind border furrow; S 1 continuous, transverse to convex posteriorly, with deeper lateral por tions; S2 and S3 poorly impressed, latter at level of anterior of palpebral lobe; frontal lobe mar ginally longer than others of equal length. Oc cipital furrow weB-impressed with deeper pits laterally just adaxial from axial furrow, with anteriorly convex shallower medial part. Occipi tal ring shoder than Ll, with posteromedian node. Axial furrow poorly impressed but dis tinct. Preglabellar field short, depressed, with wide median ridge running from front of glabella (i.e. out of subdued parafrontal band) into anterior border; anterior border furrow deep, with steep anterior wal1, with row of indistinct pits in bottom of furrow laterally; anterior border long, slightly shorter medially, convex in section with steep posterior rise, with highest point be hind midlength and gentler anterior slope, covered with discontinuous comarginal terrace lines. Palpebral lobes typical of Redlichia with anterior end beside axial furrow forward of S3
268
STEFAN BENGTSON et al.
Fig. 179. Redlichia guizhouensis Zhou in Lu et al.,19 74. A, righ t thoracic pleura NMVP1] 2911. B, fragmentary hy postome NMVPl 12914. C, pygidi u m NMVPl12896. 0, librigena NMVPl12901. E-I, cranidia NMVP 112905, 112912,112903, 112907, 112889. All x4, except C,F, x5 and H, x2.
and posterior also close to axial furrow near midlength of occipital ring; interocular cheek narrow (1/3 basal glabellar width); palpebral fur row well impressed; palpebral lobe upturned latera l l y, of uniform width . Facial suture transverse for short distance from anterior of palpebral lobe then curving gently forward to widest point on posterior part of border before running axially across border at high angle to margin; anterior part of fixigena relatively small and bearing transverse terrace lines. Librigena with high eye socle, with narrow genal field of almost uniform width, with long curved advanced genal spine. Pygidium smooth, convex; axis occupying most of width but relatively short, consisting of one short ring and bilobed terminus; behind two low bulges of terminus the sloping border area extends to transverse posterior margin without doublure. Pleural area of one segment with two pleural bands exsagittal and apparently ending in small marginal spine.
Remarks. This species may be considered inter mediate between R. nobilis Walcott,1905 and R. chinensis Walcott ,1905, both widespread in China and the latter in Australia. However, the proportion of greatest anterior width to cephalic length being 1.1 instead of 1.4 or more as in R. chinensis and the low pygidium with short axis and gently sloping posterior border are specifi cally distinctive. The glabella and interocular cheeks are narrower than in R. nobilis but this is probably the most closely related species. R. guizhouensis may turn out to be synonymous with R. nobilis but for the moment the pygidia (cf. Fig. 179C with Zhang & Jell, 1987, p1.7, fig.4) are distinctly different. However, Red lichia is known to contain species dimorphic in their pygidia and with only one pygidium as signed to each species at th� moment that pos sibility cannot be ignored. Although known to Etheridge in 1919 and collected by many people in the intervening years this must still be considered a poorly
""
\ }
EARLY CAMBRIAN FOSSILS, S. AUST.
known· species because only one Chinese cranidium� is assigned to it and it is represented in Australia by exoskeletal fragments with un damaged pieces of exoskeleton extremely rare� A larger number of specimens will be necessary to assess intraspecific variation. Redlichia endoi Lu,1950 (Fig.180) 1950 Redlichia endoi Lu, p.166, pt. 1 , fig.B-4. 1965 Redlichia endoi Lu; Lu et al., p.59, pl.7, figs 6,7. 1980 Redlichia endoi Lu; Zhang, W.T. in Zhang,
W.T.et al., p.129, pl.22, figs 1,2. Material. Holotype Lu et ai., 1965, pt .7, fig.6. Australian material assigned NMVP113296, 113298, 113301,. 113309, 1 13310, 113313, 113322, 113327, 113334, 113'336, 11 3339, 113340, 127091127096, 127101 fr om NMVPL1499 a n d NMVPI03468, 103470, 103477, 1 03488, 112879,112886,112887,127051, 127162 from NMVPLI00 scree on the southern slope of the same ridge as NMVPLI499, near Wirrealpa Mine, Wilkawillina Lst. Diagnosis. Large member of Redlichia with dis continuous poorly impressed glabellar and oc cipita] furrows, with anterior cranidial width about equal to cephalic length, with short occipi tal spine; fine tuberculate ornament; pygidium subquadrate, with axis of one ring and long bilobed posteriorly rounded terminus separated from posterior margin by short flat border area, apparently with one pair of marginal spines at end of single exsagittal pleura that drapes around axis. Description. Large species with cranidia up to 30mm long; anterior profile with broadly convex glabella - barely elevated above flat fixigenae; lateral profile with steep rise up anterior glabella then almost imperceptible rise to posterior mar gin. Ornament of fine granules weakly organized into short ridges over surface except for border, palpebral lobes and furrows. Cranidium as wide across anterior border (Le. �-�) as it is long. Glabella occupying c. 4/5 cephalic length, with straight sides converging gently forward to well rounded anterior, in the largest individuals re,:" aching close to the border furrow but in smaller specimens «22 mm cephalic length) separated by a discrete preglabellar field; three pairs of glabellar furrows discontinuous;·S1 narrow but prominent at axial furrow, shallowing rapidly posteroaxially; S2 similar but narrower and less transverse; S3 as an area Jacking ornament and subtly depressed; glabellar . lobes of c. equal
269
length at axial furrow except for longer frontal lobe; occipital furrow transverse, discontinuous, and represented by deep sharp apodemal pits laterally; occipital ring shorter sagittally than laterally, with short posteromedian spine and granular ornament forming into comarginal ter- . race lines along posterior margin. AXial furrow well impressed but shallowing around anterior, deepest and narrowest at posterior margin. Preglabellar· field short, c. 1/2 anterior border length, slightly elevated above fixigenae to sides and made up of many close spaced· ridges (caecae) running from parafrontal band into anterior border; anterior border furrow well im pressed, with large faint pits in lateral parts and faint shall owing in front" of glabella. Anterior border of uniform length and evenly convex in sagittal section, with faint irregular comarginal terrace lines on marginal two thirds. Anterior parts of fixigenae triangular, with preocular ridge running from anterior· of palpebral. lobe in straight line to1Jorder furrow a short distance forward of facial suture., with indistinct furrow running from neat slight bump at midwidth of anterior part of facia] suture· adaxiaJly almost parallel to border furrow but gently converging to that furrow. Palpebro-ocular ridge extending forward of eye just outside axial furrow to form indistinct parafrontal· band; ocular part arcuate, with both ends close to axial furrow; palpebral furrow distinct but shallow, running from axial furrow anteriorly and descending and turning laterally behind rear of palpebral lobe into border furrow without meeting axial furrow, palpebral lobe of uniform width,· flat to laterally rising in transverse section, with both ends descending; posterior cephalic limb wide and short, typical of Redlichia. Facial suture running forward from anterior of palpebral lobe_ at low angle to transverse, with bump about halfway to border furrow where it turns slightly forward, then curv ing more strongly forward from border furrow and running adaxial to margin over anterior half of border. Librigena with low eye socle, convex and des cending genal field becoming wider posteriorly; border furrow becoming wider and shallower and border becoming wider and flatter posterior ly; border with comarginal terrace lines on outer half extending down advanced genal spine.. .. Pygidium small, convex, smooth. Axis of short articulating halfring, one ring and longer bilobed terminus finishing forward of centrally ex cavated posterior margin. Pleural area with one exsagittal segment, terminating in long' pro minent marginal spine extending a short distance beyond posterior margin.. Remarks. Distinctive features are the incomplete
270
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS� S. AUST.
occipital furrow, generally inconspicuo,us glabellar furrows'and occipital spin�;:-glabellar shape, size of anterior part of fixigena and aligned tuberculate ornament are also dis-' tinctive. R. mansuyi Resser & Endo,1937 is probably the most similar form but its better impressed glabellar furrows, narrower interocular cheeks and lack of occipital spine distinguish it.R. takooensis has an occipital spine but has no preglabellar field, narrow interocular cheeks, better impressed glabellar furrows, longer occipital spine and anterior section of facial suture at slightly gr,eater angle to transverse line. The pygidium seems identical with that of R. f1'}ansuyi but a complete specimen is not available -and better material should be sought.
271
Pygidiu:m with pair of marginal spines at ends of exsagittal pleurae of anterior pygidial segment, with slight medial embayment in posterior mar gin and axis finishing well before margin. '
Description. Individuals upto 30cm ,long and 14cm' wide in material available; Daily �t al. (1979, p.16) quoted a size range to 35cm length for material from this locality. However, it is not certain that the same species is being discussed as outlined in Remarks below); with well developed ornament of discontinuous linear ridges breaking up into aligned' tuberculate (usually asymmetrical tubercles) in many places ' such as down into border furrow or around median thoracic nodes but becoming ,more continuous in others such as on the border and Redlichia takooensis Lu, 1950 (Fig.181) smooth in others such as in furrows and on most 1950 Redlichia takooensis Lu, p.166, pl.1, fig.C-4. post-cephalic pleural areas. 1950 Redlichiameitanensis Lu, p.167, pl.l, fig.B-l. Cranidium gently convex; glabella straight 1957 Redlichia takooensis Lu; Lu, p.261, pl.139, sided� tapering gently forward to well·rounded fig.I. anterior in border furrow; three pairs of lateral 1957 Redlichia meitanensis Lu; Lu, p.261, pl.138, glabellar furrows weakly impressed and disconfig.16. tinuous axially. Occipital ring as long as L1, 1965 Redlichia takooensis Lu; Lu et al., p.65, p1.9, drawn out medially into strong spine extending fig.l. beyond fifth thoracic segment at least. Eye ridge Redlichia meitanensis Lu ; Lu et al., p.67, p1.7, leaving axial furrow at, low angle adjacent to 1965 fig.17. anterior of L3, continuing forward around frontal Redlichia takooensis Lu; Zh an g W.T. et aI., 1980 lobe as parafrontal band often indistinguishable p.130, p1.23, figs 1-14. from the ,frontal lobe. Palpebral lobe convex in 1980 ' Redlichiameitanensis Lu; Zh ang W.T. et al., section, gently arcuate in outline, not extending 22 , figs 3,4. p. 1 29, p1 far laterally but with posterior tip almost at Redlichia takooensis Lu; Lu, pt.1, figs 10-16. 1981 posterior of occipital ring in axial furro\\'. Facial 1985 Redlichia sp. Conway Morris & Jenkins, suture leaving eye ridge a short distance from p.170, figs 1,3. axial furrow, then running forward' af 75° to exsagittal line in straight line to middle of border Material. Holotype Lu et al., 1965, pI. 9, fig. 1 then swinging sharply' adaxialIy to margiri. and Zhang W.T. in Zhang W.T. et al., 1980, pI., Posterior cephalic limb short and wide as- in other 23, fig.13. Au s t r a l i a n m a t eri a l r e f e r r e d species of genus. NMVP127003-127018 from NMVPL15 96, Librigena with low eye socle becoming higher Kangaroo Island, Emu Bay Shale. at posterior, wide flat genal field bearing caecal ornament running away from �axial furrow at. Diagnosis. Member of Redlichia with long anterior of L1 ,and swinging forward and being glabella reaching border furrow in average to broken up into pustules towards border furrow; large specimens; with long occipital spine reachborder with flat upper surface, with sharp ing beyond fifth thoracic segment; narrow interanterior marginal point where facial suture meets ocular cheeks; eye ridge in contact with anterior margin, of uniform length but widened at base of a nd lateral margins of frontal glabellar lobe then ,genal spine then narrowest behind spine" with leaving axial furrow near anterior of L3; anterior well-developed continuous terrace lines parallel to the' margin and extending the length of the part of facial suture diverging forward at 75° to ex sagittal line to leave a moderately 'large genal spine; genal spine advanced, gently taper anterior area of fixed cheek. Thorax of 15 seging, reaching as far as the anterior of the pyg ments with a strong median spine on the tenth idium. se gment extending beyond the pygidium. Hypostome crushed beneath glabellar anterior .
Fig. 180. Redlichia endoi Lu,1950. A-D, cranidia NMVP113322, x2; 127093, x4; 127162, x6; 113336, x2. E-G, pygidia NMVP127095, x10; -112886, x10; 113333, x2. H, librigena NMVPl12887, x1.5. I,J, dorsal and anterior views of cranidium NMVP103468, x5. K,L, dorsal and anterior views of cranidium NMVPl03470, x2.
M, damaged cranidium NMVP113334, x2. N, small librigenaNMVPl13327, x4. 0, pygidium NMVP127051,
"
272
STEFAN BENGTSON et al.
Fig. /8/. Redlichia takooensis LU,1950. Dorsal views of articulated individuals, variously incomplete, NMVP127015, 127014, 127004, 127013, 127011, respectively. B,D,E latex casts. A-C, x1.5; D,E, x2.
of most specimens but details unclear. Rostral plate almost as wide as anterior cranidial border, with concave lateral margins. Thorax of 15 segments, pleural areas relatively narrow, with short stout pleural spines directed posterolaterally in first 10 segments becoming more exsagittal, shorter, and more broadly based in posterior segments, long slender medial spine on tenth segment extending beyond rear of the pygidium although attitude in life is not certain. P y gid i u m with broad axis not reach ing
posterior margin, strongly bilobed o n posterior and with single ring furrow defining short anterior ring. Pleurae consist of a single pleural band running exsagittally along side of axis and terminating in short blunt marginal spine. Border area flat and ill-defined but evident behind axis and disappearing anteriorly on both sides. Posterior margin with extremely shallow median embayment. Remarks. This species from Kangaroo Island has
273
EARLY CAMBRIAN FOSSILS, S. AUST.
been referred to in the literature on several oc casions (Glaessner inSprigg,1955; Daily, 1956; Pocock,1964, 1970 and others). Although Daily (1956, p.132) considered the long occipital spine n ovel among species of Redlichia, Lu had erected R. takooensis a.nd R. meitanensis six years earlier with just such a feature. Interesting� ly Daily et al. (1979, fig.15) illustrated a spec imen from 'east of the mouth of The Big Gully' that is not readily identifiable as R.takooensis as it appears to lack the occipital spine. This would need to be confirmed on the external mould of that specimen. Kangaroo Island material col": lected just east of the mouth of Big Gully by the author conforms to the illustrations of adult R. takooensis (Zhang W.T. in Zhang W.T. et aZ:, 1980, p1.23� fig. 14) and R.meitanensis (Zhang W.T. in Zhang W.T.et al.,1980, p1.22, figs 3,4) in every tespect� Differences are apparent when compared with 'immature R. takooensis (Zhang W.T. in Zhang W.T. et al., 13) but these are' considered, due to ontogeny. ZhangW.T. (in ZhangW.T.et al., recorded 14 thoracic segments in R. takooensis based presumably on the slightly disarticulated specimen illustrated (Zhang, W.T., in Zhang, W.T. et al., medial spine on the 10th segment. The four seg ments beh.ind this macrosegment are common to Australian and Chinese specimens so that the suggested different positions of the macroseg ment may not be attributed to different mor phogenetic stages although the Chinese spec imen is in the lower part of the size range of the Australian individuals. I suggest that disarticula tion behind the cranidium on Zhang's specimen has caused the loss of one segment so that in fact the spine is on the eleventh segment, in line with most species of Redlichia and the thorax is com posed of 15 segments. Redlichiid indet. 1 (Fig.182�D)
Material. NMVP113121, 113122, 113125 from NMVPL99, Bunyeroo Creek, Parara Lst.
of frontal lobe then coming close' again . near occipital furrow, gently convex in section" elev ated above interocular cheek; palpebral furrow ' distinct. Librigena 4mm long without genal spine (3mm), low eye socle, broad genal field widest at base of genal spine; border furrow well-im� pressed, shallower behind spine; border gently convex in section, relatively narrow, widest at base of spine, terrace lines parallel to margin continuing down spine; genal :spine relatively short, advanced, with tip curving adaxially. .
Remarks. The palpebral lobe suggests Redlichia where possible relatives are R. noetlingi or R. mansuyi Resser & Endo,1937 as indicated by the narrow interocular cheeks, relatively short genal spine with tip curving adaxially and almost im perceptible S3�, Redlichiid indet. 2, described below, shares the narrow interoculat cheeks but its glabella is mpre convex and the glabellar furrows are a different with deeper pits in the axial furrow. Whether these are specific differen ces or not is uncertain. These two indeterminate redHchiids may belong to a differentgenus such as Syndianella Lu,1961 particularly as Redlich iid indet. 2 has indications of a longer preglabel lar field' and almost bulbous glabellar anterior. Material available is' too incomplete for iden tification.
Redlichiid indet. 2 (Fig. 182A)
Material. NMVP127002 a cranidial fragment, 7mm long, from NMVPL1584, north of Mount Ragless, Parara Lst. Description. Glabella convex particularly in frontal 10Qe, with broadly rounded anterior giving appearance of being slightly truncated,' lateral gIabellar furrows deepest in small pits at axial furrow then extending almost impercepti� bly adaxiaIJy. Preglabellar field flat but extent unknown beyond the 2mm preserved. Interoc ular cheek extremely narrow, tapering over longer distance forward to produce a half tear drop shape. Palpebral lobe leaving axial furrow at midlength of frontal lobe and returning lo axia1 furrow or almost so at level oiLl (intervening parts of lobe not available).
Description. The cranidial fragment is 4.5mm long a.nd includes only the right side of the glabella and the right palpebraUobe. The glabel la is moderately convex, with thre pairs of lateral glabellar furrows; SI, well-impressed, almost sinuous in shape, with slightly deeper pit lateral Remarks. This incomplete specimen is discussed ly adjacent to but not in axial furrow, S2 shal above under Redlichiid indet. 1. lower but wider and longer than SI, S3 barely evident, meeting axial furrow behind eye ridge. Redlichiid indet. 3 (Fig.182E-H, J-N) SO transverse, shallow; occipital ring short. In terocular cheek barely wider (at its widest point) than palpebral lobe., Palpebral lobe broadly ar- . Material. NMVPl13017, 113018" 113021, 113025, 113026, 113039-113044, 113056, cuate, meeting axial furrow adjacent to posterior
274
STEFAN BENGTSON etal.
113057 and 113060 from NMVPL83, Mt. Scott Ra., Ajax Lst.
from NMVPL1599, from west of Wirrealpa Spring, Oraparinna Shale.
Description. Glabella gently convex, well-im pressed l·a teral furrows h aving deepened apodemal pits laterally within them, glabellar furrows usually reaching axial furrow but in one specimen (Fig.182E) SI ending before reaching axial furrow. Glabella reaches anterior border furrow with broadly rounded anterior. Anterior border flat to gently convex, with prominent almost continuous terrace lines extending ventrally over whole of rostral plate. Eye ridge leaving axial furrow at rear of frontal lobe. Pal pebral lobe relatively wide, flat to gently convex, dropping down steeply 1-2mm from axial fur row to border furrow at rear, defined by well impressed palpebral furrow. Interpcular cheeks moderately wide but a tangent of a cirde only not a semicirCle. Librigena with wide genal field, fairly flat wide border covered with comarginal terrace lines extending down the advanced genal spine. Thoracic segments typically redlichioid.
Description. Posterior half of librigena with coarse tuberculate ornamentation on genal field and inner part of border, without ornament in border furrow and with finer comarginally aligned granular ornament on outer half of bor der; genal spine relatively short and probably a little advanced.
Remarks. The bioclastic limestones at this locality contain many trilobite remains with ex oskeletal components upto c. 6-7mm in maxi mum dimension usually preserved whole where as larger components are almost invariably frac tured and incomplete. This indicates a relatively high energy environment in which a significant concentration of moulted trilobite exoskeletons was washed around and fractured. Fragments of the three species identified are readily distin guished by the coarse ornament of Eoredlichia shensiensis, and Pararaia tatei is a smaller non redlichioid trilobite. Other material available, al ways fragmentary, represents this redlichioid that grew to large size. Its features are consistent with Redlichia but could belong to another allied genus with the rear of the palpebral lobe dose to the axial furrow. On available material further identification is not possible. Numerous red1ichioid pygidia from this locality are all assigned to E. shensiensis but it is possible that pygidia of the two are so similar as to be inseparable. Redlichiid indet. 4 (Fig.182I) Material. NMVP127042 a fragmentary librigena
Remarks. This incomplete specimen is tenta tively ide�tified as a redlichioid but may well belong in another group. It is recorded here only because species of trilobite with this type of ornamented librigena are otherwise unknown at this horizon in the Pararaia janeae Zone:
Family DOLEROLENIDAE Kobayashi,1951 This family has ha" a varied history with discus.,. si ons or u s a g e s! b y a nUf!?ber of authors (Sdzuy,1959; Repina, 1966; Opik,1967; Raset ti,1972; Zhang, W.T. inZhang, W.T. et al. ,1980) leaving its understanding quite unresolved. Ap parently almost arbitrary family· groupings of some authors add to confusion in the group; details of ventral and post cephalic morphology as well as morphogenetic details of already es tablished genera are urgently needed to under s t a n d p h y l o g e n y b e fo r e a t t e m p t i n g a dassification. Most of the genera involved are . known from cranidia only making their com parison with more completely known genera quite impossible, particularly when postcephalic featur es a�e . taxobases (Opik, 1967; Zhang,W.T. in Zhang, W.T., et al.,1980). It is not my intention to review the family but to make observations that bear on the affinities of the species attributed to this broad group below and the bearing of those observations on the family concept. Similarity ofimmature cranidia of O. rubra sp. nov., of Dolerolenus zoppii (Meneghini, 1882) and Anadoxides armatus (Meneghini, 1881) from the Dolerolenus Zone of Sardinia, and of Eoredlichia intermedia (Lu,1940) and Wutin gaspis tingi (Kobayashi,1944) is quite striking, strongly suggesting familial relationships; sub sequent development of different adult mor phologies needs further evaluation. Opik's
Fig. 182. A, Redlichiid indet. 2, cranidial fragment NMVP127002, x6. B-D, Redlichiid indet. 1. B,D, cranidial fragments NMVP113125, 113 121, x6.5. C, librigena NMVPl13122, x5. E-H, J-N, Redlichiid indet. 3. E-G, cranidial fragments NMVP1 13042, x4; 11302 1, x2; 113043, x3. H, librigena NMVP113056,x4. J,L,M, pygidia NMVP113055,x5; 113065,x5; 113070, x7. K, fragment of large librigena NMVP 113057, x2. N, part of cephalic doublure (left), palpebral fragment (centre) and librigena of Eoredlichia shensiensis (right), NMVP 113041, x3.5. I, Redlichiid indet. 4, fragmentary librigena NMVP 127042,x2.
EARLY CAMBRIAN FOSSILS, S. AUST.
275
276
STEFAN BENGTSON et al.
(1967) separation of Metad oxididae a n d Dolerolenidae may ultimately prove correct but for the present it seems more sensible to take the broader view of Sdzuy (1961) and Rasetti . (1972). In passing it should be noted tbat whereas Rasetti (1972, p.59) pointed out Sdzuy's (1961) probable mistake in assigning immature cranidia to 'Metadoxides' rather than Dolerolenus his own illustrations of the smallest cranidia of M. armatus a n d D. zoppii (Rasetti,1972, pl.14, fig.I1 and p1.15, fig.7) seem inseparable except possibly on the degree of impression of glabellar furrows and orientation of palpebral lobes - the latter being significant for generic development. Similarity.. of immature cranidia ofOnaraspis somniurna Opik, 1967and adult cranidia, albeit of small species, of Bultiiaspis Lermonto"a in Repina,1956 was noted by Opik (1967, p.151) and ·assignment of that Russian genus· to the Dolerolenidae on this basis is borne out by the similarity of tlje immature cranidia of O. rubra, A. armatus and D. zoppii as meritioned, a..bove. One feature�hat mitigates:against this family grouping is the rostral plate of Dolerolenus and Abadiella being qllite wide (Rasetti, 1972, p1.16, figs 2,'14, 15}as opposed to the situation in O. rubra 'sp. nav: where it must have been very narrow or absent (probably the latter).'This fea ture 'is no.rmally relatively uniform through a trilobi te family but until that structure is described for a 1,1 members of Sdzuy's family grouping its usefulness in taxonomy cannot be evaluated. I 'am not in'possession of enough biostratigraphic information or sufficiently com plete morphological understanding to be able to suggest any lineages within this group. Rea/aspis Sdzuy, 1961 based on R� streilOid�:S Sdzuy,1961 f r o m the Lower C ambrian of Spain and Onaraspis have in common the truncated glabel la, ,no preglabellar field, the transformation, through growth of the conical glabella into the truncated adult form, similar palpebro-ocular structure, p'ossibly same, rostral structure and most importantly similarly shaped pygidia with the axis finishing forward of the posterior mar- . gin. These may prove to belong to a separate lineage. A,badiella , Lunolenus and Wutingaspis (?=Eoredlichia) may represent another with Dolerolenus in unc�rtain relationship closer to the latter lineage th�n the former while Ana doxides may be c10ser to the former. A great deal more information is needed on all these genera as cephalic comparisons alone are not sufficient to define relationships. The close pygidial comparison between Yorkella Kobayashi, 1942 and Abadiella huoi as well as similarities of cephalon and thorax indi� cate that Yorkellaalso belongs to· this broad group.
AbadieJla Hupe,1953 1953
Abadiella Hupe,p.205.
1966
Parabadiella Zhang,p.163.
1980
Parabadiella Zhang; Zhang W.T. et al., p.173.
1985
Parabadiella Zhang; Chen,p:332.
1985
Parabadiella (Danangouia) Chen,p.333.
Type species. Abadiella bourgini Hupe,1953 from the Amouslekian Zone of Daguinaspis and Resserops at ,Ouijj ane southeast of Tiznit, Morocco. Diagnosis. Redlichioid with conical to trunca toconical glabella with three pairs of lateral fur rows; occipital furrow and ring elongate and drawn out posteromedially into spine. Pregla bellar field with prominent wide median ridge running from parafrontal band into anterior bor der. Eye lines strongly oblique, undifferentiated from palpebral lobes, dividing at axial end into a parafrontal· band and a posterior trunk entering the frontal lobe of the glabella; palpebral lobes we1l away from axis. Discussion. Hupe (1953) based this genus on a Moroccan species that he i11ustrated with a draw ing and profile only. Through the courtesy of Prof. A.R. Palmer I have been able to examine latex casts of the types of A. bourgini and A. meteora and suggest that they are synonymous because the features· of the axial end of the eyeline and glabellar shape used to distinguish the species, are artefacts of prese rvatio n. Parabadiella Zhang, 1966 was erected for P. huoi Zhang, 1966 from the Early Cambrian Kuochiapa Formation of southern Shensi and based on relatively undistorted larger specimens than the Moroccan material; this species has no features of any substance that might be used to separate'it from Abadiella. Moreover it has a parafrontal band giving rise to a strong median ridge on the preglabeUar field, a characteristic palpebro-ocular ridge, occipital spine and glabellar features that necessitate assignment to Abadiella. Subsequently erected Chinese species ofAbadiella (Zhang, W.T. in ZhangW.T., et al., 1980; Chen,1985) are based on internal moulds in shale making it difficult to establish the exter nal features of the species but their assignment to Abadiella seems reasonable. Parabadiella (Danangouia) Chen, 1985 was differentiated by Chen on its lack of medial ridge on the preglabel lar field, less prominent parafrontal band and lack of an occipital spine. However, illustrated specimens of the type D. transversa Chen,1985 apparently 'internal moulds in shale, are alll damaged at the rear of the occipital ring, uridea,r in the preglabellar field because of damage or
EARLY CAMBRIAN FOSSILS, S. AUST.
extraneous material except his pI.l, fig.3 'where the medial ridge is obvious and unclear in the proximal end of the palpebro-ocular ridge (traces of the parafrontal band are evident in his pI. 1, figs 2,3,4). Neither Chen's (1985) illustrated material nor his discussion justify subgeneric separation of Danangduia and it' is here placed in synonymy with Abadiella.
277'
decreasing forward to transverse S1 at level of middle of eye line; S 1 'with deep pit laterally, shallowing towards axis; S2 of uniform depth; Ll'and L3 longer than L2 and frontal lobe that is relatively short. Occipital furrow well im pr�ssed, with deep lateral pits and longer shallow , axial section; occipital ring tapering laterally, drawn out medial into a stout posterior spine Qf , variable length, more or less flat in exsagittaJ_ Abadiella huoi Zhang,1966 (Figs section or becoming slightly convex laterally. , 183A-G,J, K, 184) , Preglabellar field as long as frontal lobe,' with wide (1/2 glabellar width) prominenfridge incor Parabadiella huoi Zhang, p.164, pt.l, figs 1,2. porating many finer ridges (i.e. closely spaced 1966 Parabadiella huoi Zhang; Lu et aI., p.87, 1974 caecae) and running from parafrontal band into p1.33, fig. 1. rear of anterior border, shorter than anterior part 1975b Dolerolenus? sp. novo Opik, p.4l, p1.7, fig.2. of fixigena behind border furrow. Anterior bor 1980 Parabadiella huoi Zhang; Zh;;tng W.T. in der furrow distinct as a change in slope from , Zhang W.T. et al., p.174, p1.46, figs 1-6. downsloping cheek to' convex border; anterior border convex, longer and less convex laterally, Material. Holotype NIGP18139 (Zhang,1966, with 3-4 comarginal terrace lines along anterior pl.1, fig.I). Paratype NIGP18140 (Zhang, 1966, margin. Fixigemi just less than half glabellar' p1.1, fig.2). Australian material NMVP111804, width at level of widest point on palpebral lobe, 1 ' 27053-127069 from NMVPL78, Curramulka, moderat�ly convex. Eye line continuous with Parara Lst.; NMVP112948, 112955, 112957, palpebral lobe, of two trunks separating �xially 112971, 112973, 112979, 112980, 112983 , with posterior one going into frontal lobe of glabeJIa and anterior one into parafrontal band. 112984 and 112988 from, NMVPL1498 near ) Wi r r e a l p a Min e , Wil k a w i l l i n a L s t . a n d Palpebral lobe short, gently arcuate, at level of NMVP111805, 127105-127156 from NMV ' midlength of glabella or a little to'the posterior,. PL1503, Mt. .�cott Ra., Ajax Lst. CPC13189 gently convex, defined by well-impressed' pal pebral furrow that runs to the axial furrow behind' described by Opik (1975b, p1.7, fig.2) from the Kulpara district in the same sequence as the the eye line �md becomes shallower to axis and at midlength of palpebral lobe. Facial suture Hummocks Section but at an uncertain horizon leaving eye line well away from axis, diverging , although Opik (1975b) indicated an horizon forward to midlength of border then . curVing probably low in the sequence. obliquely' at low angle to margin; behind eye ' Diagnosis. Member'of Abadiella with relatively suture sigmoidal, reaching posterior margin on, flat anterior border, with comarginal terrace lines short distance lateral, to palpebral lobe but at along anterior margin, with relatively narrow eye much lower level. Posterior border furrow long, line but long palpebral lobe, with ,preglabellar deeper posteriorly, running from axial furrow in ' front of posterior margin slightly forwa�d, be median ridge more than half basal glabellar width, with occipital furrow long and barely comirig longer and sl:1allower on lateral descend evident axially ,but with sharp apodemal pits ing posterior part of fixigena. Posterior border, short, convex, beco�ing slightly longer laterally, laterally; pygidium subquadrate, with single ring defined on axis and long terminus, with single with relatively IOI)g posterior slope to margin becoming flatter and longer a� a facet on lateral exsagittal segment in pleural area having spine ' slope from point of geniculation. on tip at posterior margin just abaxial to axis; entire surface with fine pustules grading down in Librigena with high eye socle distinguished size away from prominent parts of exoskeleton. from wide genal field by right angled change in ' s10pe; genal field with narrow flat band adjacent Description. Cranidium slightly longer than to eye soc1e occupying. 1/3 width then rolling over into geritly convex slope to border furrow; width across palpebral lobes, up,to 25mm long. Glabella relatively narrow, 1ittle more than one bord�r furrow well impressed but with shallower third of cranidial width, tapering forward with section just forward of genal spine. Border flatly. amount of taper increasing slightly anteriorly so convex, with prominent comarginal terrace lines on marginal rol1 continuing down length of genal that sides are gently convex forward of mid spine. Genal spine as long as rest of librigena length, with narrowly rounded anterior situated well behind anterior border furrow; three pairs of near base and stout, rising in flat sigmoidal curve from border but continuing curve of margin in lateral glabellar furrows well impressed, with degree of impression and angle with transverse dorsal view. Doublure widest anteriorly and at ,
I
,
2'115
STEFAN BENGTSON et al.
Fig. 183. A-G,J,K, Abadiella huoi Chang ,1966. A,B, dorsal and ante rior views of cranidium NMVPl11804, x3 and x4.5, respectively. C, cranidium NMVP127050, x3, with bradoriid at far right. D, cranidium NMVP127053, x4. E, librigena BM In 36299, x3. F,G, disarticula ted thorax and pygidium NMVP111805, x2 and x5 respectively. J,K, damaged cranidia NMVP127055, 127056, x 2.5. H,I, Abadiella sp. cf. A. huoi. H, cranidium NMVP1l2965, x3. I, pygidium NMVP112949, x5.
base of spine; with terrace line at marked change of slope from convex marginal roll to flat dorsal ly rising adaxial part, with this terrace line peter ing out near base of spine and distinct ion
between parts not evident on short posterior doublure. Sutural margin shows anterior exten sion as part of dorsal border then anterior roll and uneven ly chev ron-shaped rostral suture.
EARLY CAMBRIAN FOSSILS, S. AUST.
Rostral plate with few terrace lines near anterior margin, with one,prominent terrace line towards posterior at marked change in slope continuing from librigenal doub , lure, uneven posterior margin, with concave late;:al margin against unevenly chevron-shaped rostral suture; in sagittal section with short part of anterior marginal roll, longer flat part to last terrace line then dorsally sloping posterior part.· Thorax of 13 or more segments, highly convex with free pleura steeply downsloping, slope decreasing in more posterior segments; articulating half ring almost as long as ring itself and much lower, tapering laterally; articulating furrow long, well-impressed, with apodemal pits laterally; articulating ring with median spine of . variable length arising from full length of ring and extending up and only slightly back. Pleura with long well-impressed furrow, horizontal for 1/2 width then sharply downturned to pleural tip (horizontal part becoming smaller" percentage towards posterior), pleural tips spinose and be-' coming more curved to posterior along thorax. Pleural bands short, simply ridges where walls of pleural furrow turn over to slope to margins. Articulating facet 1/2 segmental length at its greatest length. Doublure beginning at point of. geniculation on posterior, elongating slightly toward tip and extending over entire length for distal part, with small posteriorly projecting spine on adaxial margin. Pygidium small, convex, without border. Axis occupying most of area, more or less parallelsided, well-rounded and extending to the margin posteriorly, articulating half ring short, highly arched, tapering laterally, articulating furrow well-impressed, longer than half ring with which it is lower than rest of a xis, with sm all posteromedial notch into first ring giving furrow greater sagittal length; one ring furrow�distinct, with sharp apodemal pits laterally and quite shallow over sagittal line, with pair of shallow indistinct pits laterally representing second ring furrow, both ring furrows increasing in definition with growth. Pleural region consisting of single segment wrapped back along side of axis, with - pleural furrow exsagittal, with wide anterior pleural band and posterior band lost into axial furrow, with pointed tip of segment· at margin beside axial furrow. Doublure narrow laterally, absent anteriorly and posteriorly. Ornament of fine granules over prominent dor- sal parts of exoskeleton, but not in furrows, muscle scars, or on ventral parts, and finer on pygidium and thorax than on cranidium.
,/
Remarks. This material, preserved as original exoskeleton in limestone at Curramulka and silicified in a muddy limestone in the Mount
'
279
Scott Range, provides the first detailed mor phology of'the genus because previously de scrib,edspecimens are internal moulds. WithiIiA. hu61 the occipital spine, the preglabellar medial ridge, the parafrontaL band and omament are variable features.
A,badiella huoi may be distinguished from the Moroccan type species' by glabellar shape and segmentation, smaller more slender occipital spine, arid relatively broader cranidium.Abadiel la tenuilimbata Zhang W.T. & Lin in Zhang W.T. et al.,1980,A. obscurata Zhang W.T. & Lin in Zhang W.T. et ai.,1980, A. sp., and·A. sha anxiensis Zhang W.T. & Lin in Zhang W.T.et ai.,1980. are all smaller specimens than those illustrated .ofA. huoi and some of them may be immature forms of A. huoi. Although their lack of an occipital spine, if confirmed, might sep. arate A. huoi, each collecting locality. should be. . searched for a growth series and latex casts froin external moulds made to confirm these species. This species is presumably'the one that Daily (1956) mistakenly identified from Curramulka Quarry as Y. australis (Woodward, 1884) butA. huoi from Curramulka is easily distinguished from Y. australis by the better impressed glabel lar furrows, different glabellar shape, preglabel� lar median ridge, shallower longer' occipital furrow with sharp apodemal pits, differently shaped palpebro-ocular ridge, aJ?d more quaqrate pygidium with ]e�s inflated axis. AmongA. huoi from Curramulka there is variation in le. preglabellar field and in one or two spe.cimens (Fig. 183B) the glabella does approach the anterior border furrow but' the combination of features particularly the preglabellar median . ridge is always sufficient for 9istinction. Two cranidia figured by Opik (1975b, pl.7, fig.2) as Dolerolenus? sp. novo are assigned to here on glabellar shape, preglabellar field, palebro-ocular structure and correspondence of all observable features inc1uding ornament. Abadiella huoi is interpreted to be a variable species based on the illustrated material from China (Zhang W.T. in Zhang W.T. et aI., 1980) and from each of the Curramulka and Mount Sc ott Range localities in South Austra"lia. Chinese and Australian material exhibit the same range in preglabellar length with the Curramulka material perhaps indicating the glabella closer up to the border than the Chinese. However, it must be remembered that the Chinese material is flat tened in shale and in removing the convexity of the glabella this tends to elongate the steeper preglabellar area. The Chinese specimens show better impressed g labellar furrows than the Australia� ones but again compression may have deepened the furrows in the internal mould.
280
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
Abadiella sp. cf. A. huoi Zhang,1966 (Fig. 183H,I)
lichia. Therefore, I consider Pachyredlichia to be a junior subjective synonym of Eoredlichia. Moreover, there seems liUle point in distinguish ing a subgeneric category on type of ornament. Features used to distinguish Eoredlichia from Wutingaspis (Zhang W.T. in Zhang W.T. et al., 19-50, p. 160) may well be considered to be of specific importance only and I suggest that the two are synonymous, particularly as their ranges 'are apparently exactly coincident. However, without the type material before me and with most of the Chinese species of these two genera illustrated with internal moulds only I refrain from introducing this synonymy at this stage.
Material. NMVP112949, 112965 at NMVPL 1498, Old Wirrealpa Mine, Wilkawillina Lst. Discussion. This cranidium has a relatively smaller glabella with curved S2, relatively long anterior border and long occipital spine. While none of these characters removes it from the range of variation in A. huoi their combination does make it noticeably different and - it is here isolated to highlight its different possibly 'end member' morphology. Similarly the pygidium has a third axial segment, well-impressed pleural furrows and strongly bilobed axial terminus, but these fe atures are found among silicified specimens from Mt. Scott Ra. so the variation is almost certainly intraspecific.
Eoredlichia shensiensis (Zhang,1966) (Fig. 185A-J) 1 966
Eoredlichia (Pachyredlichia) shensiensis Zhang, p.153, pI. 1, figs 5,6.
Eoredlichia Zh��g,1950
1 974· Eoredlichia (Pachyredlichia) shensiensis
1950
1 980
1953 1953 1953
Zhang; Lu etal. , p. 87, p1.32�. figs 7,8.
Eoredlichia Zhang, p. 10. .
.
1980
Archaeops Hupe, p. 194.1962 Eoredlichia
1965
Eoredlichia Zhang;Lu etaI., p.67.
1966
Eoredlichia (Pachyredlichia) Zhang, p. 153.
1980
Eoredlichia Zhang; Zhang W.T. in Zhang
Material. Holotype NIGP18143 and paratype NIGP18144 from the Kuochiapa Formation, Liangshan, Hanchung, southern Shenxi. Aust -ralian material NMVP103498, 112868, 113028, 113069, 113034, 113035,- 113036 113037, 127038 from NMVPL83, Mt. Scott Ra., Ajax Lst.
Pachyredlichia Zhang; Zhang W.T. in Zhang W.T. etaI., p. 157.
Type species. Redlichia intermedia Lu,1940· from the late Chiungchussu Stage of southwest China; by original designation. Discussion. The diagnosis of Pachyredlichia Zhang,1966 reveals no features that could be used to distinguish P. shensiensis Zhang,1966 from Eoredlichia except perhaps for the pustulose or tuberculate ornament. However, orna ment is known to vary considerably within the Redlichioidea (e.g., in Redlichia, see Opik, 1970; Zhang et a/., 1980, pI. 17) and it seems highly likely that the same may be true within Eored-
Pachyredlichia zangshanensis Lin & Yao in Zhang etal., p. 158, p1.38, fig. 14;p1.39, . figs 1--4.
W.T. etal., p.151. 1980
Pachyredlichia shensiensis Zhang; Zhang in Zhang etal., p. 157, p1.38, figs 9�13.
Eoredlichia Zhang; Zhang, p. 121. Saukiandops Hupe, p.193. Zhang;Zhang, p. 36.
V
. 281
--
Discussion. The immature cninidium (Fig. 185C�E) is coarsely granular except in furrows; its glabella tapers forward- to rounded anterior, with three pairs of lateral glabellar furrows, well impressed occipital furrow with lateral apodemal pits and occipital ring with short spine, glabella separated from strongly convex medially shor tened border only by deep border furrow, eye line evenly curved, palpebral lobe narrow almost ver tical, deep palpebral furrow running frpm axial furrow behind eyeline into posterior border fur-
Fig. 184. Abadiella huoi Chang, 1966. AlJ silica replacements. A-D,G, fragmentary thoracic segments in dorsal view NMVP127144, 127125, 127134,127128,and 127147,respectively,All x5, except D, x4. E;'Tostral plate in ventral view, NMVP127124,x5. F,H,ventral view thoracic pleural tips showing second spine at adaxial edge of doublure NMVP127146, 127127, respectively,x5. I-M,pygidia in dorsal view NMVP127123, 127132, 127129, 127126, 127131, x4, x6,x6, x8, x5, respectively. N,O, librigena in ventral and dorsal views NMVP127145, x2. P,Q, librigena in ventral and dorsal views NMVP127133, x2. R,1ibrigena in dorsal view NMVP127110, x3� S,T,W,AB,cranidia, in dorsal view NMVPJ27122, 127117, 127113, -127116,repectively, x2, x3, x2, x3. U,V, dorsal and anterior oblique views ofcranidi!lm NMVP127105, x3. X,Y, dorsal and anterior oblique views of cranidium NMVP127114, x2. Z,AA, dorsal - and anterolateral oblique view- of cranidium NMVP127106,x2.
282
STEFANBENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
283
'\
row behind eye, large posterolateral cephalic Description. Glabella subquadrate, with trun limb as wide as interocular cheek occupied main cated anterior at border furrow and rounded ly by long border fur:ow, short conr.ex I?osterior corners, SI shallow; SO well impressed, with border strongly gemculate Qear mldwldth and' strong apodemal pits laterally; preglabellar field anterior section of facial suture diverging for absent; anterior border furrow deep, deeper and ward at small angle to exsagittal line before more V-shaped in section across front of glabel turning sharply near the midlength of the border la, shallowing and becoming more V-shaped in to run obliquely for some distance to margin at section laterally, anterior border convex in sec low angle. Mature specimens (Fig.185A,B,G) tion, becoming slightly longer and flatter lateral have relatively smaller surface tubercles, distinct ly, eyeline low but wide in even curve from axial apodemal pit in the axial end of SI, less convex furrow behind glabellar anterior; palpebral lobe prohably straight parallel-sided glabella,. facial with sharper curve in posterior section but with suture that diverges at slightly greater angle for posterior tip still far distant from axial furrow, ward of the palpebral lobe, eye line that is about rising steeply laterally out of palpebral furrow same length as width of palpebral lobe and forms with outer part flat and well above narrow inter a straight line from axial furrow almost to the ocular cheeks; posterolateral cephalic limb long midlength of the palpebral lobe where a fairly and wide, with long posterior border furrow run angular curve brings the posterior tip back into ning from axial furrow near midlength of occipi-, --" same exsagittal plane as anterior tip, palpebral tal ring to be deepest' near geniculate lateral lobe upflared laterally at about 450, postero articulation then shallowing slightly to facial su cephalic limb wide and long with post lateral ture; facial suture diverging slightly forward to - (3 just forward of border furrow then curving erior border furrow occupying 1!2 length. Mature specimens are comparable with E. strongly axially to cros� border at low angle to shensiensis Zhang,1966 with no discrepancies as anterior margin. Librigeml'with low uniform eye far as comparison is possible. The immature socle without ornament; genal field conv�x cranidium has some differences in glabellar and . anteriorly with sfeep slope into border furrow, , palpebral shape, in anterior border and border less convex more gently sloping and wider furrows as well as a few other minor points. p osteriorly; border furrow well im,pressed, However, when the morphogenetic series of lowing posteriorly; border wide, gently convex other species of Eoredlichia (Zhang et al., 1980, in section, becoming less convex poSteriorly, p.90, pIs 32-35) are compared most of these with coarse tubercles becoming lower but dis,.. tinctly elongate parallel to margin �ear rear and features are represented in immature stages of along genal spine; genal spine long, stout, con one or more of those species in the same expres sion as in the South Australian specimen. tinuing curve of lateral margin; anterior marginal projection long and pointed along anterior of E. zhangshanensis Lin & Yao in Zhang et ' facial suture on border; doubhire unknown. al.,1980 which is a junior subjective synonym of Thoracic segments varying, along length of E. shensiensis, is known from an immature cranidium (Lin & Yao in Zhang et al., 1980, thorax, with anterior ones having wide transverse p1.38, fig.14, lefthand specimen). This specimen , pleurae and posterior ones having marked posterior swing in the shorter and narrower is 2-3 mm shorter than the immature South pleurae. Axis with medial spines (although only Australian cranidium (Fig. 185C-E) but shows the anteriorly rounded glabella, relatively coar a few were observed it is worth noting that none of the available axial rings lacks a spine). Pleural ser omament, curved eyeline plus palpebral lobe, furrow elongate to occupy most of segmental long posterior border furrow and less divergent length at axial furrow, slightly narrower but anterior limb of facial suture. deeper in articulating line near midlength, then shorter and with steep anterior wall behind large sp. (Fig.186) smooth slightly concave facet on free pleura, petering out some distance from the tip; pleural tip bearing short posteriorIy curved spine; Material. NMVP127026-127037 from NMV pleurae geniculate in articulating line; posterior PL1594, Wilkawillina Gorge, Wilkawillina Lst.
Eored�ia
Fig. 185. A-l, Eoredlichia shensiensis (Zhang,1966). A,B, dorsal and anterior views of large cranidium NMVP127038, x3. C-E, dorsal views and oblique view of small cranidipm NMVPI03498, x2.S.C, latex cast. F, left thoracic pleura NMVP113028, xJ. G, latex cast of cranidial fragrnentNMVPl12868, x3. H, latex cast of librigena NMVP11303S, x4. 1,1, pygidia NMVP113069, 113029, xS. K-O, Yorkella sp. novo K,L, right anterior and dorsal views of cranidium NMVPI03476,xS. M, dorsal view of cranidium NMVP113297, x4. N, dorsal view ofcranidium NMVP11329S, x6. 0, dorsal view of librigena NMVP113340, x6.
284
STEFAN BENGTSON et al.
Fig. 186. Eoredlichia sp. A,C,H-J, cranidial fragments NMVP127037, 127031, 1 27029, 127035, 127035, x4.5 except C, x5.5; J, x3.5. B, librigena NMVP127032, x3. D-G, pygidia NMVP127026, x5; 127034, x4; 127028, x4; 127036, x6.
thoracic segments are very strongly turned posteriorly beyond their pleural midwidth, lack ing an articulating facet, having shorter more uniform pleural furrow remaining in midlength . throughout. Pygidium subquadrate, inflated; axis occu pying most of area, extending to and dropping almost vertically to posterior margin; articulat ing half ring short and convex, articulating fur row only slightly shorter, flat-bottomed, laterally tapering; first axial ring defined by well-im pressed laterally deepened transaxial furrow, with short wide posterior excavation repre senting half ring of second segment; a second axial ring of similar length to first faintly defined by shallow discontinuous transaxial furrow; ter minus with rounded posterolateral corners, with
prominent bulges on posterolateral corners giving distinctly bilobed appearance; axial fur row not impressed, having its position defined only by marked change of slope; pleural areas very narrow, upturned laterally, with wide prominent anterior pleural band of first segment ending in short marginal spine; anterior pleural furrow well impressed, running exsagittally and facing out to the marginal spine; a second, less obvious, pleural furrow running close along the lateral base of the axis behind the first transaxial furrow. No border defined. Entire surface of exoskeleton with coarse tuberculate ornament grading into furrows and down slopes where the lowest parts are smooth; tubercles on pygidium much less obvious than on more anterior parts.
/
EARLY CAMBRIAN FOSSILS, S. AUST.
Remarks. This taxon is extremely poorly known particularly with respect to the glabellar regiori so inferences regarding its affinities are tentative. However, it appears similar to the material from Mt. Scott Range described above as Eoredlichia shensiensis being distinguishable only by the much steeper posterior to the pygidial axis, the lack of co-marginal terrace lines on the anterior border, apparently more poorly impressed glabellar furrows and coarser tuberculate orna ment overall. A new species is probably repre sented but is not so mimed until more complete material is available.
285
section of facial sutures. Xela also bears some resemblance to Pararedlichia Hupe,1953 par ticularly P. ovetensis Sd zu y i n L ifia n & Sdzuy,1978 in glabellar shape and in eye lines running into the front of the glabella. However, it may be distinguished from the Spanish species by its sharply impressed SI, the wide border, straight eye line, short depressed preglabeIlar field, and wide posterior cephalic limb. Among species of Redlichina Lermontova,1940 the type (R. vologdini from Siberia) is �istinctive in its glabellar shape and in the pygidium but R. ler montovae Pokrovskaya (1959, pIA, figs 8-11) bears strong resemblance in most respects except Xela Jell, gen. novo for SI. However, the pygidium of that Siberian species of the Rhondocephalus Zone of the Etymology. With the specific epithet, an anagram Lenian (=Toyonian) Yarns, is not yet available from Alexander; for Alexander Jell who helped and it may be premature to effect a· transfer especially until the significance of the sharp SI collect in the Flinders Rariges over five field seasons. . in redlichioid taxonomy is fully understood. Al though affinities are obscure I have included itin the broad concept of the Dolerolenidae where Type species. Xela drena sp. noy. some apparently allied genera may be placed. Diagnosis. Large, coarsely tuberculate, with Xela drena Jell, sp. novo (Figs 187,188) anteriorly rounded glabellalerminating anterior ly before border furrow; anterior limb of facial suture at 45° to exsaggital line isolating large Material. Holotype NMVP127161; paratypes NMVP I034 6 5, 1 03467, 112074, 112878, anterior part of fixed cheek forward of eye, inter 113293, 113295, ·113299, 113301, 113302, ocular cheek extremely. small; palpebral .lobe S3. 113304, 113306, 113308, 113311, 113317, short; eye line meeting axial furrow behind 113318, 113323-113325, 113330-113334, Pygidium with three short rings. and distinctly 113337, 113338, 113341, 113342, 113344� bilobed terminus, posterior margin excavated; 113349, 113351, 113397, 127071-127090, pleural area of three segments each with pleural 127097�127101, 127102, 127157-127161 all furrow and the first with marginal spine. from NMVPL 1499, east .of W�rrealpa Mine, Discussion. This large species that inhabited the Wilkawillina Lst. Othertnaterial NMVPI03464, 103471, 103475, 103478, 103479, 103482, waters around an archaeocyathid bioherm is not 103483, 103485, 103490, 103493, 103494, cleaily related to any known form although its 103496, 112872-112877, 112879, 112883 from redlichioid affinities seem assured from the pal NMVPLI00, scree on southern slope of same pebral strncture and type of pygidium. Its glabel ridge as NMVPLI499, Wilkawillina Lst. lar shape, long anterior border, pits in the border furrow, short palpebral lobe, ornament, occipital Diagnosis. As for genus. tubercle, and glabellar furrows suggest alliance with Drepanopyge Lu,1961, in particular, the Description. Large species with largest cranid type species, D. mirabilis LU,1961 from the ium available 60mm long; ornament of coarse lower Tsanglangpu Stage in eastern Yunnan. granules except in furrows, on the anterior border However, the pygidium, while developing a an d on· posteri o r parts of pygidial axis. larger me'ural area than in most redlichioids, does . not Vave the number of segments or margmal . Cranidium with axis standing above flat or laterally rising fixigcnae in anterior profile; spines seen in Drepanopyge arid its axial ter lateral profile rising up anterior of convex glabel,. minus and posterior margin are quite different la from convex border and concave preglabeUar also. The pygidium in Xela resembles that of field, then dipping a little over L1 before rising Kuanyangia Hupe, 1953 from the Chiungchussu again to rear of occipital ring. Glabella straight Stage in Yunnan (some doubt is expressed about and parallel-sided forward of SI, tapering for the accuracy of the sketch "provided by Zhang et ward along Lt; anterior broadly rounded not al. (1980, fig.56.12) below under discussion pf Y orkella sp. nov.) but has more axial rings .. reaching border furrow. SI continuous, with lateral parts angling back from axial furrow but Moreover, the cranidium" of Kuanyangia differs ·transverse and markedly shallower across axis, in glabellar shape, glabellar furrows, and anterior
286
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
with apodemal pits just lateral to the transverse section and another at axial furrow; S2 discon tinuous, poorly impressed, transverse except for slight posterior curve at axial end; S3 faintest, transverse, just behind junction of eye line and axial furrow, S4 angling forward from axial fur row just forward of where eye line meets axial furrow; frontal lobe quite short. SO well im pressed with apodemal pits sharper and deeper laterally, then shallower and transverse to anteriorly convex over axial half of glabellar width; occipital ring 'of uniform length, as long as Lt in sagittal line, with prominent median tubercle near posterior margin. Preglabellarfield short, depressed; anterior part of fixigena large and triangular; anterior border furrow with row of small pits in deepest part, pits more numerous laterally; anterior border relatively long and con vex in section with small insignificant plectrum, smooth except for extremely fine irregular ter race lines more or less parallel to margin. Eye line short, at low angle to exsagittal line, running across axial furrow into anterolateral corner of glabella. Palpebral lobe continuous with eye line, . kidney-shaped, rising laterally, widest at mid length, defined by distinct but shallow palpebral furrow, relatively short in extending from level of S2 to that of midlength of Lt, with posterior tip well away from axial furrow. Posterior cephalic limb long and wide, with anterior mar gin sloping gently back not far behind transverse from rear of palpebral lobe and turning sharply posteriorly near e xtrem ity, border furrow uniformly long, meeting axial furrow near anterior of occipital ring, parallel to posterior margin; posterior border shorter than furrow, of uniform length to articulating point then becom ing more elongate laterally. Facial suture diverg ing at 450 from anterior of palpebral lobe that is a short distance from axial furrow level with posterior of L3, turning sharply adaxially about 1/3 of distance across border, then curving across border adaxially at high angle to margin. Librigena with low unornamented eye socle, wide tuberculate and gently convex genal field, distinct well-impressed border furrow. Border wide, convex, with tuberculate ornament giving way to terrace lines near margin that extend d genal spine; tubercles becoming elongate posteriorly near and on genal spine. Genal spine with broad base, relatively short, continuing even marginal curve. Hypostome markedly convex, with rather
rn
287
coarse reticulate ornament on median body and comarginal lines on border; maculae prominent elongate depressions shallowing posteriorly but continuous over axis in curve parallel to margin, with projection (posterior wings) in lateral mar gin adjacerit to maculae; border furrow not im pressed; border uniform and little differentiated except by ornament.Thoracic segments with well-impressed pleural furrow in midlength, petering out down pleural spine, and having steeper anterior than posterior wall; articulating facet little differen tiated but represented by transverse smooth area wi th fi ne transverse ridges on outer margin gradual1 y turning to exsagittal down pleural spine. Ornament of coarse tubercles�long two pleural bands becoming elongate towards the pleural tip. Anterior descent to margin relatively gentle with fine narrow ridge at margin; posterior vertical to convex so margin is tucked under pleural band. Width of pleural parts of segments varying along length of thorax. Doublure with coarse, irregular terrace lines more or less transverse to long axis of segment and small but prominent spine or tubercle posteriorly just below inner margin of doublure. Pygidium moderately convex in posterior profile, horizontal in lateral profile except for steep posterior slope on axis, coarsely tubercu late except in furrows and on articulating half ring and rear of axis. Axis of three rings plus terminus that extends almost to posterior margin; articulating half ring shorter than articulating furrow, low and sm ooth; rings elevated, separated by long deep transverse ring furrows, with short wide excavation in rear of first ring; terminus distinctly bilobed and truncated poste riorly, with indistinct posterior apparently just inside margin. Axial furrow not impressed and position defined by change in slope between axis and pleural field and by change in direction of axial rings-pleural bands. Pleural areas of three segments; pleural furrows well impressed,· al most exsagittal anteriorly and more so posterior ly; interp]eural furrows not impressed at all; first segment with wide anterior pleural band bulging laterally in its posterior half, with strong mar ginal spine at its tip. Posterior margin strongly excavated in some specimens whereas in others there is only a weak excavation and greater de scent from rear of terminus, posterior doublure absent in both types.
Fig. 187. Xela drena Jell,gen. et sp. novo All cranidia, A,B, juveniles; C,D,G, larger but still small specimens. A, NMVPI03494,.xl0. B, NMVPl12872, x6. C, NMVP127073, x2. D, NMVP112878, x4. E, NMVp127161, x2. F, NMVP127075, x1.5. G, NMVP127100, x5. H, NMVP112074, x2. I, NMVP113299,x4. J, NMVP113330, x1.5.
288
STEFANBENGTSON et al.
Morphogeny. The smallest cranidium available . pointed tubercles. Pygidium occupied mainly by axis extending to posteriorniargin without is <3 mm long, has the glabellar anterior trun cated against the anterior border and apparently doublure, with small pleurae of one segment bilobed anteriorly, has the occipital furrow much having expanded anterior pleural band and pair better impressed than S1, has the palpebral lobe of marginal spines elevated above margin of well.away from the glabella and lacks the coarse axIS. ornament. At 6mm length the cranidium has the truncated glabellar anterior still in the border Discussion. Yorkella has never been satisfacto . furrow, palpebral lobes situated far laterally, the rily described or classified because it has been occipital node well-developed, SI well im known from specimens in limestone where full pressed, and the ornament becoming coarser. mechanical preparation' is . virtually impossible. Only with acid etching of material from the type With growth from this stage the glabella gradual locality have. all parts of the exoskeleton been ly becomes anteriorly rounded and moves a little revealed. Th e h o l o t y p e i s an exfoliated further back behind the border furrow, the border becomes relatively longe�, the palpebral lobe cranidium badly damaged in several key areas. moves towards the glabellar posteriorly becom . Essential proportions and shapes. are used to match exoskeleton to exfoliated holotype as well ing more exsagittal,_and SI becomes more sharp. - ly impresSed. as the fact that only. one species with any resemblance at all occurs in the Ardrossan area. Once the silicified material is attributed, identity Remarks. Intraspecific variation has not been . assessed due to the small number of specimens as a redlichioid is quickly established on the available of any one size. However, variation in features of the palpebro-ocular ridge, thoracic segments and pygidium. pygidial posterior has been noted above and some variation in relative widths of L1 andL2 is Whereas Daily (1956) recorded Y. australis at Curramulka, Horse Gully, Mt. Scott Ra., and evident. Wilkawillina Gorge I have found it only at Horse Assignment of other parts of the exoskeleton Gully and in the Hunimocks Section near Kulto this species" is by the coarseness of the orna ment in the case of thoracic segments and . para. His other identifications, certainly Cur ramulka and Mt. Scott Ra., almost certainly refer pygidia, and by the size in respect of large to Abadiella huoi. Hbrigenae. However, small librigenae and hypostomata are not assigned with as much cer"' Yorkella may be distinguished from Wutin tainty'- It was not possible- to differentiate these gaspis and Eoredlichia by its extremely wide elements for Xela as opposed to the sympatric . glabella without glabellar furrows, almost ex species of Micmaccopsis so all have been as sagittal anterior limb of the facial suture, and signed to the more common species X. drena. pygidium with posteriorly expanded axis and small, short, pleural areas. It resembles quite YorkeJla Kobayashi,1942 closely Kuanyangia Hupe, 1953 from south western China in glabellar shape, palpebral 1942 Yorkella Kobayashi, p.492. shape (at least its type species K. pustulosa (Lu, 1941) but K. granulosa Zhang, 1966 has a much Type species. Conocephalites australis Wood shorter palpebral structure), thoracic structure, ward,1884 from Yorke Pe ninsula, Sou th pygidium, and ornament but that genus is distin Australia; by-monotypy. guished by the course of the facial suture, better impressed glabellar furrows and shorter pal Diagnosis. 'Redlichioid siniilar to Wutingaspis pebral lobe. The pygidium of K. granulosa as but with large, strongly convex glabella 2/3-4/5 depicted by Zhang, W.T. in Zhang, W.T. et al.,1980, fig. 56.12 presumably drawn from as wide as long and with lateral margins either parallel or gently converging in anterior part, Zhang W.T. in Zhang W.T. et aI., 1980, p1.43, with broadly rounded glabellar anterior in fig.8 with two pleural segments is the �nly red anterior border furrow, with glabellar furrows lichioid pygidium having one axial ring and two pairs'of p1eurae terminating in marginal spines. incomplete across axis, with ornament o f coarse
Fig. 188. Xela drena Jell, gen. et sp. novo A-C,P, librigenae NMVPI03478, 103493, 127071, and 113317, repectively x5, x3, x3, xl. D, pygidium NMVP127099, x4. E,F, dorsal and posterior views of pygidium NMVP127098, x4. G,H,dorsal and posterior views of pygidium NMVP113293, x4. I,K, lateral and ventral views of large hypostome NMVP127101, x2. J,--hypostome NMVP1l2879, x3. L, ventral view of thoracic pleural tip showing terrace Jines and small tuberc1e at inner edge of doublure NMVP103465, x5. M-O, thoracic pleurae NMVPl13345, 103467,112883, respectively, x2, x4, x5.
EARLY CAMBRIAN FOSSILS, S. AUST.
.
289
290
STEFAN BENGTSON
et at. .
Y orkella australis (Woodward,1884) (Figs 189,190)
specimens but may be a short depressed area in some. Anterior border furrow well-impressed, shorter laterally, sometimes noticeably elongate 1884 Conocephalites australis Woodward,ip.344, in front of the glabella: Anterior border semicir pt.11, fig.2a,b. cular in sagittal section, becoming slightly less Ptychoparia howchini Etheridge, p.2, pIA. 1898 convex laterally, with prominent comarginal ter 1919 Ptychoparia? australis (Woodward); race lines on the steep anterior part, with terrace Etheridge, p.384, p1.39, fig.6. lines more numerous laterally where new ones Ptychoparia? howchini Etheddge; Etheridge, 1919 begin just axially from facial suture. . I. p.385, p1.40, fig.7. Fixigena narrow, gently convex. Eye line of 1935 Solenopleura austrt;llis (Wood�ard); same width as palpebral, lobe and continuous Kobayashi, p.262, 265, p1.24, figs 18, 19. with it in gentle even curve from axial furrow to Protolenus howchini (Etheridge); Whitehouse, middle of eye then slightly more strongly curved 1936 p.73. axially to rear of eye. Palpebral furrow distinct 1939 Protolenusaustralis (Woodward); but shallow, extending behind eye line to axial Whitehouse, p.214. furrow. Facial suture extending almost exsagit Yorkella australis (Woodward); Kobayashi, 1942 tally forward from anterior of eye and diverging p.492, figs 5,6,9,10. laterally only a short distance from rear of eye. Posterior border furrow well-impressed, running Material. Holotype BM 12349. Other material slightly forward from posterior margin at axial NMVPl12550-112596 127103, 127104 from furrow so that posterior border becomes longer NMVPL76, Horse· Gully,· Parara Lst.; this is lateral to articulation point, furrow shallowing probably the type locality or at least the origin of and hmgthening down steep narrow posterior the rock in which the holotype was. found; cephalic limb. NMV P l12933, 112938, 127 0 7 0; NMVP Librigena with low eye socle delimited from 112598, 112616, 112619, 112624, 112631, genal field by change in slope rather than furrow; border becoming slightly wider posteriorly 112634, 112636, and 112637 from NMVPL96, Kulpara, Parara Lst; AMF5092, holotype of before extendinginto strong genal spine directed Ptychoparia howchini. slightly axially, with strong development of comarginal terrace lines on l(iteral rol1 of border, Diagnosis. As for genus. terrace lines decreasing in number at base of genal spine and not extending ventrally beyond Description. Cra n i d i u m as w i d e a s l o n g , the angular change in curvature to a flat doublure moderately convex, upto 25mm 10ng. Glabella rising strongly to finish close to the dorsal exos relatively wide, c. 47% of cranidial width, with keleton at the border furrow; posterior border straight sides converging gently forward to well much shorter than width of lateral border of low rounded, anterior extending to just behind border convexity and with extremely short doublure. furrow; three pairs of lateral glabellar furrows Facial suture along inner margin sigmoidal be almost imperceptible externally but more ob hind eye and curving strongly axially across vious on internal mould especially SI;SI deeper anterior border only to return abaxially as con at sagittal end and running forward towards axial nective suture across doublure. furrow;S2 and S3 almost transverse and ex . Rostral plate with a few comarginal terrace tremely shallow; S3 transverse at level of junc lines adjacent to rostral suture, with single ter tion of eye ridge with axial furrow. Occipital ring race behind midlength where sagitta] section changes from horizontal to rise dorsalIy to the (excluding spine) 1/5 of glabellar length, defined by continuous ,occipital furrow having distinct hypostomal suture; connective sutures straight, apodemal pits laterally, slightly shorter laterally, converging forward; posterior a ragged edge ap with short stout occipital spine extending parently not a sutural margin in all available horizontally. Preglabellar field absent in most specimens. Hypostome unknown. Fig. 189. Yorkella australis (Woodward; 1884). All silica replacements except h-N. A, dorsalview of pygidium NMVP112578, x6. B,ventralview of pygidium NMVJ>112557, x6. C,D, pygidia NMVP112574, 112579, x6.
E,F,ventral and dorsalviews ofrostral plate NMVPl12594, x4. G,H, dorsal andventralviews of right thoracic pleura NMVPl12569, x5. I, two posterior thorac:'ic segments fused on right side NMVPl12588, xS. J, ventral view of left thoracic pleura showing spine at inner edge of doublure, NMVP112575, x5. K, pygidium NMVPl12562, x6. L-N, dorsal, lateral, and anterior obliqueviews ofhoJotype internal cast BMJ2349 x3. O-Q, lateral, dorsal and anterior obliqueviews of large cranidium NMVP112591, x2.5. R, pygidium NMVP112568, x6. S,T, right librigenae NMVP112551, 112559, x3.
EARLY CAMBRIAN FOSSILS, S. AUST.
291
292
STEFAN BENGTSON et al.
Thorax of unknown number of segments showing considerable variation from front to rear particularly in decreasing convexity, in decreas ing size of medial spine and in increasing retral swing of free pleurae. Articulating half ring short in most specimens (Fig. 1901) but in others, usually those of low convexity with little retral s win g of p l e u r a e o c c u p y i n g 1/2 l e n g t h (Fig. 190G). Ring usually "transverse and of uniform length but elongate laterally and shorter medially in those with long half ring, with longer medial spine arising from full length of ring and rising up then back in convex segments with shorter medial spines arising from posterior of ring only in transverse segments of lower con vexity. Axial furrow well impressed, not e]{sagit� tal but running around marked bulge of axis at junction with pleural furrow. Pleural furrow well impressed sharply defined, straight (except in more posterior ones where there is a retral curve similar to margins) from axial furrow behind anterior margin to finish in midlength near ex tremity .. Anterior pleural band shorter than posterior except in posterior segments where they are equal in length. Articulating facet begin ning at axial furrow but short laterally to point of geniculation then slightly longer and slightly concave on distal part, length and demarcation of facets decreasing to posterior. Pleural tip with short, distinct spine directed posterolaterally (posteri, Pygidiuin.· relatively small, convex, without defined·border. Axis occupying most of area, more or less parallel-sided, well rounded and extending to margin posteriorly; articulating half ring short, highly arched, tapering slightly laterally; articulating furrow well-impressed, longer than half ring with which it is lower than the first ring;one indistinct transaxial furrow 1/4 of length behind articulating furrow, with wide apodemal pits laterally, with vague suggestion of another represented only by pair of lateral pits near midlength of axis. Pleural region consisting of single segment wrapped back along side of axis, with pleural furrow exsagittal, with wide anterior pleural band and narrow posterior band, with pointed tip of segment at margin beside axial furrow. Doublure narrow laterally, absent anteriorly and posteriorly. Ornament of coarse tubercles over prominent
dorsal parts i.e. not in furrows, muscle scars, border, doublure or rostral plate. �
.
Remarks. This species is readily separated from other redlichioids including Kuanyangia by its poorly impressed lateral glabellar furrows; it is distinguished from Yorkella sp. novo in discus sion of that species below. Although silicified material provides superior morphological detail it presents problems in comparing flattened specimens in shale so thaJ great care must be taken with comparisons between ·different types of preservation to ignore features induced by \ tectonic distortion or by comparing different sur faces of an exoskeleton. Y orkella sp. nov. (Fig. 185K-O) Material. NMVP103476, 103469 from NMV PLI00, NMVP113295, 113297, 113340 from NMVPL1499 near Wirrealpa Mine, Wilkawil lina Lst. Description� C-ranidium widta= length without anterior border, strongly convex, with anterior of glabella descending steeply to border furrow in lateral profile;axis broadly convex and standing aboye convex cheeks and upturned palpebral lobes in anterior profile; surface ornament of extremely fine network of reticulate ridges with small depressions between, giving impression of a punctate surface, most prominent on higher parts and disappearing into furrows. Glabella twice as long as wide, reaching anterior border furrow, with straight parallel sides posteriorly, tapering slightly in anterior part and well rounded anteriorly;four pairs of glabellar fur� rows quite indistinct as areas devoid of ornament and faint depressions, S4 and S3 running obli quely forward from axial furrow at and just be hind proximal end of eye line respectively;SO sharply impressed, with wide slightly deeper apodemal pits laterally but not reaching axial furrow;occipital ring relatively short, with short posteromedian spine directed up and back. Axial furrow distinct but poorly impressed with pair of rather long oblique fossulae-that are barely per ceptible. Preglabellar field absent. Anterior bor der not available. Anterior part of fixigena large. Eye line wide, sli.ghtly obJique just behind trans-
Fig. 190. Yorkella australis (Woodward�1884). All silica replacements except A and R. A, cranidium AMF5092, xl.5, holotype of Ptychoparia howchini Etheridge Jr, 1898, B, cranidium NMVP112572, x3.C,D, anterior and oblique views of thoracic segment NMVP112590, x3. E,H, anterior and dorsal views of thoracic segment NMVP112595, x3. F,I, posterior and dorsal views of thoracic segments NMVP112592, x3. G,J, dorsal views of thoracic segments NMVP112585, 112596, x3. K, right librigena NMVP112581, x3. L,M, large cranidium NMVP112584, x4. N-T, ·cranidia NMVP112571, x3. 0,112556, x4. P, 112587, x2. Q, 112580, x4. R, 112634, x2.2. S, 112573, x3. T, 112582, x2.
EARLY CAMBRIAN FOSSILS, S. AUST.
293
294
STEFAN BENGTSON et al.
EARLY CAMBRIAN FOSSILS, S. AUST.
295
verse, continuing into long narrow palpebral lobe available for a precise dating; by original - desigwith even, moderately convex curve; palpebral. nation. furrow narrow, distinct, beginning anteriorly at start of palpebral lobe, becoming slightly deeper -Discussion. The genus was fully discussed and and sharper posteriorly as it curves down and its affinity with Anadpxides and Bulaiaspis cor laterally behind palgebral lob�; palpebral lobe rectly recognized by Opik ( 1967). Rasetti (1972, rather flat and only weakly upturned laterally in p.60) questioned this relationship on the grounds section, with both anterior and posterior ends of differences in thorax and pygidium while ac well away from. axial furrow and posterior end knowledging some cr.a nidial resemblances just a little further laterally. Posterior cephalic which he inferred to reflect homeomorphy par limb long and wide, with well-impressed border ticularly in view of the great age difference. furrow becoming deeper laterally on steep de . However, the thorax of O. rubra is quite similar to that of Dolerolenus zoppii (Meneghini) from scent beyond lateral articulating point. Posterior Sard ini a (Rasetti, 1972) in bearing incon border short and sharply convex but elongating toJateral articulating point then flatter, longer spicuous median nodes, having long pleural fur and downsloping laterally. Facial suture barely rows and extended pleural tips with w ide diverging forward from anterior palpebral lobe, doublures; the thorax of D. zoppii is not far I1l:nning obliquely behind palpebral lobe, not different from that of Anadoxides armartus reaching close to axial furrow at either end of (Meneghini) so the thoraxes in these 3 genera palpebral lobe. may be considered at least co-familial. Pygidia of Dolerolenus and Anadoxides which Rasetti Remarks. This material is distinguished from (1972, p.56) considered to have unquestionably co-occurring taxa by the ends of palpebral lobe close relationship, are as distinct from each other as each is from the pygidium of Onaraspis so this and corresponding points on facial suture being cannot be used as a family feature. However, situated well away from axis, and on the distinctive ornament. Individuals of similar size from pygidia similar to those of Onaraspis have been the growth series of Xela drena are readily dis- . ascribed to the related Bulaiaspis(Repina, 1966, tinguished by their less convex, anteriorly sub- .pl.8, fig. 11; p1.12, figs 15,16) which belongs to the Dolerolenidae. Moreover, the great temporal quadrate glabella having continuous SI and by the much coarser ornament. It is assigned to separation noted by Rasetti is not as definite as Yorkella on the shape of the eye line and palhe assumed with Onaraspis possibly having a pebral lobe, on the almost exsagittal anterior range back into· the Early Cambrian and limb of the facial suture, and shape and ler:tgth of Anadoxidespossihly having a greater range than is represented in Sardinia (Fritz,1973; Zhang in glabella. The short anterior border, narrow palpebral lobe, and short occipital and genal spines Lu e't member of the Anadoxididae which I have dis distinguish this material from Y. australis but it is insufficiently known for erection of a new cussed above as a synonym of the Dolerolenidae. species at this stage. There is a resemblance to Onaraspis rubra Jell, sp. novo (Figs 191, Chakaskinella lita Repina in Repina et aI., 1964 but that species has shorter palpebral lobes 192A-I) situated further forward and the resemblance may be superficial. Although such a relationship Etymology. Latin rubra, red; for the n�arby Red Tank Well. is exceptionally speculative it is interesting to consider as a possibility for a lineage from the R�dlichiida to the Corynexochida. Material. Holotype NMVP113103; paratypes NM VP111811 , 11181 6, 111818-111822, Onaraspis Opik,1967 113071-113102, 113104-113119 from NMV PL89 northwest of Wirrealpa, Moodlatana Fm.; SAMP24946-24951 from the Moodlatana For Type species. Onaraspis somniurna Opik, 1967 mation in Ten Mile Creek east of Wilkawillina from central Australia, of late Early Cambrian or Gorge, exact horizon not certain (colI. by Jon earliest Middle Cambrian age, possibly the Zone athan Clarke). of Redlichia chinensis but sufficient data are not Fig. 191. Onaraspis rubra J ell, sp. novo A, juvenile cranidium NMVPl11819, x6. B, cranidium SAMP22946, x3. C,librigena NMVP113116, x5. D, ventral view of librigena NMVP113078, x3. E, juvenile cranidium NMVP113108, xio. F,G, anterior and dorsal views of craniditim NMVP113119, x4, x3, respectively. H, holotype cranidium NMVP113117, x1.5. I, ventral view of librigena NMVP1130�4, x4. J-M, pygidia . NMVPl13089, x6; 113095, x4; 111821, x4; 113097, x7.
296
STEFAN BENGTSON
et
al.
Diagnosis. Member of Onaraspis with conical glabella decreasing in convexity through growth, with longer palpebral lobes, no preglabellar field, well-impressed lateral glabellar furrows, smooth to finely pustulo�e surface and pygidium with axis of at least seven segments finishing well away from margin, with pleural ribs curved �trongly posteriorly to margin.
types of segments in different parts. One type of segment with parallel anterior and'posterior mar gins, with pleural furrow near anterior adaxially but curving posteriorly near tip to' finish near posterolateral corner at base of short spine, with laterally squared off end and margin running slightly abaxially to posterior. The second type is a macropleural segment with narrower pleural ,.area (probably indicating pos-terior situation Description. Cranidium of low convexity; ap within thorax), with massively expanded (par parently with thin exoskeleton. Glabella sub ticularly in length) anterior and posterior pleural conical, tapering forward to truncated anterior, bands, with deep pleural furrow beginning at with rounded anterolateral corriers, with anterior anterior margin in axial furrow then running at border furrow; SI and S2 long shallow, obliquely across pleural field closer to posterior transverse to .slightly· conve'x posteriorly with than anterior for most of time and continuing deeper apod�Ii1al pits laterally and continuous down proximal part of long stout posterolateral over axis; S3 barely perceptible as faint lateral pleural spine, with transverse anterior margin depr.ession just behind junction of posterioiof and strongly curved posterior margin, with steep eye line ,with axial furrow; SO similar to SI but anterior and gradual - posterior walls to pleural slightly.deeper and longer; occipital ring rela furrow, wIth anterior pleural band greatly in flated. A third type of segment is represented by tively 'short, with low median ,node behind mid the two behind the macropleural one and slopes length; axJal.furrow shallow, barely more than posteriorly . away from axis as well as tapering, faint chan'ge of slope from glabella to cheek. Anterior border furrow shallow, indistinct, as with pleural furrow close and parallel to anterior long as 'border; ante:fior border flat, short, not margin throughout, with pleural tip extended into cleatly separated from border furrow; border and lateral spine curving posteriorly. Pygidium semicircular, with moderate con furrow together shorter in front of glabella than' laterally. Fixigena smooth;with low but distinct vexity in particular of the axis standing above the broad ridge along outer edge of axial furrow gently convex pleural areas; axis occupying 0.35 extending from level of occipital ring to forward . pygidial width, of five axial rings and long �er of S2; eye line short at anterior of palpebral lobe minus of several more indistinct rings, with rings artd running adaxially to prominent node before bearing median node and separated by transaxial becoming longer with anteridr part extending to furrows having lateral apodemal pits directed anteriormost part of glabella and posterior part slightly posteriorly towards axis, with bluntly extending to posterior of frontal lobe; palpebral pointed to narrowly rounded axial posterior close lobe narrow, weakly convex laterally as defined to pygidial posterior just inside border furrow, b y broad shallow palpebral furrow, with with articulating half ring as long as an axial ring; posterior tip further from axis than anterior, ex axial furrow not impressed, represented only as tending from level of L3 anteriorly back to level change in slope. Pleural areas with three pleural of rear of Ll; facial suture almost exsagittal furrows impressed and vague interpleural fur forward of palpebral lobe, curving adaxially' rows also evident; pleural furrows with steep across anterior part of border to reach margin in anterior wall and curving strongly posteriorly short distance, from posterior of palpebral lobe near margin to be almost parallel with it, with running obliquely posterolaterally then curving anterior pleural band inflated a� marked change back to margin to leave relatively long wide of direction of furrow so that individual segments posterolateral cephalic limb. resemble the macropleural segment of the Librigena with upturned inner edge beneath thorax; border furrow in larger specimens broad eye, flat genal field, with broad shallow border and shallow, not evident in smaller specimens; border a thread- -like rim in some specimens; furrow, with flat border, with long stout ad vanced genal spine. poublure 1/2 width of doublure wide, tapering forward -- and back (its librigena at middle of eye, of uniform width in'ner edge identified by weak furrow on com except for considerable widening around base of pressed specimens) from widest point near genal spine, with convex section, with prominent anterior of terminus, with prominent comarginal terrace lines. comarginal terrace lines extending down genal spine as well as beyond facial suture anteriorly so that rostral plate is either absent Or very nar-' Morphogeny. The changes in morphology that row. . occur with increasing cranidial size are noted and Hypostome not known. those features not mentioned are assumed to Thorax incompletely known but with different enlarge while maintaining a uniform condition.
EARLY CAMBRIAN FOSSILS, S. AUST.
297
Fig. 192. A-I, Onaraspis rubra Jell, sp. novo A,B, large cranidia NMVP113106, 113103, x3. C, librigena NMVPl13083, x7. D, cranidium NMVP113085, x3. E, small cranidium NMVP111820, x 10. F, right thoracic pleura NMVPl131 01, x 10. G,H, left and right thoracic macropleurae NMVP113116, 112885, x7. I, thoracic fragment NMVP1 13102, x2. J-M, Elicicolacalva Jell, gen. et sp. novo cranidia J, NMVPl13128, x5. K, 112976, x2. L, 112967, x4. M, 112960, x2.
298
T S EFAN
These changes are observed by comparison of cranidia 4-6mm long with others up to 25mm long and are expressed as a progression from smallest up to largest -unless otherwise stated. The glabella becomes markedly less convex in anterior profile and extends further forward much closer to the anterior margin. The glabellar , anterior becomes truncated rather than bluntly rounded, the glabeUar furrows become less dis tinct and the glabella is more noticeably tapered. Palpebral lobes become relatively longer. Remarks. Generic assignment is based on low convexity, flat anterior border with truncated gl�bell�r anterior �eaching close to it, macro pleural thoracic segment and close comparison of pygidia; this assignment is valid despite lack ing knowledgt? of the number of thoracic 'seg ments which Opik (1967, p. 151) qUQted as a most important generic chara�!er. Onaraspis rubra differs from O. somniurna Opik,1967 in'its greater glabellar taper, better impressed glabellar furrows; longer palpebral tobe, lack of occipital �pi:t:le, and smooth cephalon and from O. adusta Opjk,1967 in its tapering glabella, its longer pal- ' pebral lobe, and its smooth cephalon. ,' The fractured or flexed nature of many of the exoskeletal fragments suggests poor miner alization or thin exoskeleton or both. No hypos tome or, rostra.l plate was found but the long adaxial extensiQn -of the librigenal doublure sug gests- that- a rostral plate may not have been present. ,
Superfamily ELLIPSOCEPHA LOIDEA Family UNCERT AIN Elicicola Jell, gen. nov. Etymology. Latin elix, elicis, drain or trench, colo, cultus, dwell or inhabit. Type species. Elicicola calva sp. nov. Diagnosis. Smooth cephalon except for comar ginal terrace lines along anterior margin; glabella with straight parallel sides and broadly rounded anterior finishing just behind border furrow and without furrows on external surface; axial, bor- ' der, and palpebral furrows expressed only as
changes in slope; palpebral lobe downsloping, relatively short, near midlength of glabella; posterolateral cephalic limb extending consider ably beyond palpebral lobe; rostral plate wide; librigena with border furrow impressed, border widened near genal angle, and stout genal spine. Pygidium transverse, having wide axis reaching posterior margin and two pleural segments anterior of which finishes in marginal spine.
_
Discussion. Affinities 'are not clear because of the effacement of so many features. However, glabellar shape and extent, terrace lines on anterior border, palpebral shape and position and w i de r o s t r a l p l a t e s u g g e s t t h e El l i p s o cephaloidea; the pygidium with laterally situated marginal spine, two pleural furrows and axis with large terminus forming posterior margin of pygidium is compatible. The cephalon bears some similarities to those of Paramicmacca Lermontova,1951 in particular and a number of its relatives in the Ellip socephalidae'in the smooth rather effaced cephalon, glabellar shape and virtual lack of glabellar furrows. However, the pygidium is dis tinct from that of the eIlipsocephalids because their pygidia have a 'smaller axis finishing'well forward of the posterior margin and usually lack marginal spines. In the case of Acanthomicmac ca Matthew, 1899 which has a pair of marginal spines the axis is short and tapering. Superficial similarity exists between Elicicola and Pseudoeteraspis Chernysheva,1950 from the Ketema Gorizont, Toyonian Stage of Siberia principally in the effacement of cephalic fur rows. However, the Siberian genus is distinctive in its tapering glabella, short anterior border, and principally in its pygidial struCture ( Repina, 1960, p1.5, figs 13,14) which is transverse with short relatively narrow axis and poorly defined segmentation. Its pygidium resembles that of Hsuaspis bilobata (see below) but has one fe�er p""ir of marginal spines and wider more prominent axial terminus. The pygidium could be seen as inter mediate between the t y p i c al redlichioid pygidium of this age (e.g., Eoredlichia or Abadiella) on one hand and that of Hsuaspis on the other. Familial assignment remains uncer tain.
Fig. 193 Elicicola calva Jell,gen. et sp. novo A-C,dorsal oblique and anterior views of holotype cranidiuin
NMVP103409,x2. D,E, ventral and dorsal views of librigena NMVPI03400, x3.5; 103390,x5,respectively. F�I,pygidia (F, posterior oblique view of G) NMVP103403, 103403, 112958, 112991, x8. J-L, damaged cranidia NMVPI03414,103396,103393,x2.6� M,N,partial thoracic segmentsNMVP112952,103398,x4. 0, ventral view of rostra I plate (incomplete) NMVP103404,x4. P-R,cranidia NMVP112959,x4; 103406,103407, x2.5 '
-
'
EARLY CAMBRIAN FOSSILS, S. AUST.
299
300
STEFAN BENGTSON et al.
Elicicola calva Jell,sp.nov. (Figs 192J-M, 19�): ,
Etymology. Latin calvus, bald. Material. Holotype NMVP103409 and para types NMVPI03390-103394,103396-1Q3408, 103410-103414 from NMVPL71,Kulpara, Parara Lst. Other material NMVP103460 from NMVPL 73, Kulpara,Parara L st.; NMVP 112950;-112952,112958-112960,112967, 112975,112976,112981 and ·112991 from NMVPL1498,Wirrealpa Mine,Wilkawillina Lst.;, NMVPl13126-113134 from NMVPL. 1509 west of Wirrealpa Springs,Wilkawillina Lst. Dif!-gnosis. A, Description.· Cranidium only slightly wider across palpebral lobes than long; broadly sub tr�angular in·anterior profile ancJ rising steeply over anterior half but horizontal over posterior ha:lf.in lateral profile; surface smooth except for apterior border� Glab�lla �ith straight parallel sid�s,broadly rounded anterior, with anterior end at or a short distance, behind posterior of border furrow,three pairs of lateral glabellar furrows evident only on one specimen as long wide: extremely. shallow depressions angling back towards axis; ocCipital furrow evident on a few specimens, long, shallow, transverse; occipi tar ring ,flat in lateral profile,tapering laterally, with low inconspicuous posteromedian tubercle. Preglabellar field extremely short if present at . all, with indistinct preglal?,ellar median ridge run ning forward into bord�r; anterior border furrow merely a change of slope in medial part but a . . shallow furrow laterally near suture,uniform in length; anterior border downsloping, gently con vex,of uniform length,with comarginal terrace lines around margin,terrace lines becoming finer and less continuous away from margin' cheek downsloping laterally; eye line on internal mould only,short,leaving axial furrow a short distance behind glabellar' anterior and running slightly posteriorly in straight line to anterior palpebral lobe� vague suggestions of division of eye line but not clear; palpebral lob.e ha:tf-tear drop-shaped with posterior end furthe,r from axis than anterior,downsloping laterally� of uniform .
width,defined by poorly impressed palpebral furrow,posterior border furrow,running'slightly forward and becoming longer, extending accross steeply sloping posterolateral cephalic limb that extends laterally beyond palpebral lobe fo . r distance greater thathalf palpebral lobe length. Facial suture diverging only slightly forward from palpebral lobe for some distance before curving posteriorly to margin. Posterior border short, to lateral articulating device then' much longer laterally down slope to facial, suture. Rostral plate wide,smooth,with promihent ridge at marked change of slope in section which is boomerang-shaped; r�stral. sutures and hypos' tome unknown. Librigena with narrow genal field only mar ginally wider than border; border furrow shallow and wide; border wide and flat becoming wider near base of genal spine,with comarginal terrace lines near margin extending down stout genal spine which is c. 1/2 length of rest of cheek; doublure as wide as border with marginal part 'convex and bearing comarginal terrace, lines, with distinct ridge at inner edge of·zone of terrace lines where surface turns' steeply dorsally as smooth flat surface towards dorsal exoskeleton, extending a short distance forward of facial su ture. Thoracic segments with short half ring,long flat non-tuberculate articulating ring,fixed pleura occupying only c. 1/2 width of pleura, with large flat facet sloping steeply forward on few pleurae; pleural furrow barely evident anteriorly at axial furrow,remaining close to anterior,shorter and more distinct on proximal part of free pleura then shallower and less distinct again on distal free pleura; pleural ' tip pointed but not spinose. Pygidium a little shorter than half width,al most flat except for· low . pleural areas; axis parallel-sided with short ar ticulating half ring,one ring defined anteriorly and large slightly inflated terminus extending to posterior margin without border or furrow,with shallow depression on terminus suggesting second axial segment; anterior segment on pleu ral area with wide anterior pleural band laterally after the segment curved poster!orly' in small obtuse angle with marginal spine as tip of seg ment; with short posterior pleural band and well impressed pleural furrow longest adjacent to
Fig. 194. A,B,F-Q, Pararaia tatei (Woodward,1884). A, holotype cranidiutri BMIn2350,x10. B, small cranidium NMVP103462,x12. F, pygidium NMVPl11843, x8. G, cranidium NMVP103451,x8. H, left librigena NMVP103454,x7. I,J, anterior and dorsal views of cranidium NMVP111830,x7.S: K-Q; cranidia. K, NMVPl11831,x9. L; 111835,x8. M, 111807,x6� N, 111806,x11. 0,103458,x6. P, 103420,x6. Q, 103418, x10. C E, Pararaia sp. cf. P. tatei (Woodward,1884). C,D, anterior oblique and dorsal views of cranidium -
NMVP111859,x8. E, librigena NMVP111862,x10.
EARLY CAMBRIAN FOSSILS, S. AUST.
301
302
STEFAN BENGTSON et al.
lateral articulating device; pleura of second seg- . tures of Cobbold's genus from Europe an ment indistinct but ridge running posterolaterally USSR. Such synonymy is without basis in vie\ to margin adjacent to axial furrow may be.· of these features. Moreover the South Australia) a�terior pleural band; surface finely pustulose.· :: . tC\Xon, ascribed toBigotina by Opik (1975b; pI.7 fig. 1) belongs to Alanisia guillermoi as dis Remarks. This species is distinguished on the cussed below. Its wide interocular cheeks,subtle lack of cephalic furrows and the pygidium. preglabellar boss rather than plectrum and rela� Generic relationships are discussed above. ':,tively short palpebral lobes are indicative of , Alanisia. Dis t in gui s hing f eatures· a r e the Family P�OTOLENIDAE plectrum of Pararaia, eye ridge at front of gla. bel1a in Bigotina and relatively short palpebral lobe inAlanisia. .Par:araia Kobayashi,1942 Pararaia Kobayashi, p.492. Tannuolaspis Zadorozhnaya in Zhuravleva et al.,. .,.123. , Proichangia Zhang W.T. & Zhu in Zhang W.T., ei al. ,p 241.
1942 1967
'
1980
.
.
,
.�
"
"
. Pararaia tatei (Woodward,·1884) (Figs 194A,B,F-Q, 195) 1884 'Dolichometopus tatei Woodward, p344, pLll, fig.3.
Microdiscus subsagittatus Tate, p.187, p1.2, 1892 Type species. Dolichometopus taiei (W ood fig.12. ward,1884) Parara Lst., Ardrossan. NMVPL77, Olenellus(?) pritchardi Tate, p.187, p1.2, 1892 which contains this species at Horse Gully.south fig.l1. west of the town probably yielded the type Free, cheek Tate, p.187, p1.2, fig.13. ,1892 specimen;. by monotypy. , . 1916 Redlichia tatei (Woo d ward); Wa1cott"p.359. . ' 1919 Ptychoparia (?) tatei (Woodward); Etheridge, 'Viagnosls. Protolenid with relatively narrow p.382; p1.39, figs 2,3. glabella' havi,n g, narrowly . rounded anterior; 1919 Ptychoparia (?) subsagittatus (Tate); .Ether 'glabeHar, anterIor some distance' from· anterior , idge, p.383, p1.39, figs 4,5. border furrow; prominent plectrum extending 1935 Lorenzella tatei (Woodward); Kobayashi, back to glabella. Eye ridge running into palpebral . . p.2Q9, p1.24, fig:17. lobe without change';' palpebral lobe relatively Pararaia tatei (Woodward); Kobayashi, 1942 short, finishing in ,posted,or border furrow. p.494, figs 2-4. Li brigena small, -with short- genal s pine. Pygidium transverse; largely occupied by axis, usually· with two pairs 'o� marginal spines., Material. Holotype BM 12350. From collections � by P.A. Jell.. NMVP103444, 103445, 103448Discussion. This· gehus has,been poorly under103456,103458,103461,103462 from NMVPL stood due to inadequate description of the type 73 near Kulpara; NMVP112917-:-112919, ·species" exemplified by the fact that Ghinese and. 112921, 112922, 112924, 112925 112927Ru�sian representatives have each received 112929, 112936, 112937, 112940, 112941, separate generic names. Synonymy of the. three·' 112944, 112946 from NMVPL77 Horse Gully, geneta is obvious with the narrow gl;;tbella, Parara Lst:; NMVPl13019, 113020, 1 . 13023, preglabellar field with plectrum,palpebro-ocular 113024, i 13026, 113027, 113032, 113033, ridge and overall proportions the mostsig113036, 1313042, 113045, 113048, 113052� 113053, 113058, 113061, lr13064-113067 from nificant similarities. Phy10genetic relationship is also strai'ght forWard because a comparison of its NM V -,PL83 M t. Sc ot! Ra�, Ajax Lst.; NMVP111806- 111809 from NMVPL94, J
EARLY CAMBRIAN FOSSILS, S. AUST.
303
Fig. 195. Pararaia tatei (Wo odward,1 884). A, cranidium NMVPI03461, xlO. B-D, Iibrigenae. B, NMVP1l2921, x8. C, NMVP112940, x8. D , NMVP113036, x7. E,F, anterior and dorsal views of cranidium NMVPl13067, x6 . G, pygidium NMVP113058, x20. H, latex cast of incomplete rostral plate NMVP113024,
xlO. I, cranidium NMVP112944, x6. J, cranidium NMVP112918, x6. K, two cranidia NMVP1l2994, x10. L, cranidium NMVP111839, x8. M, Iibrigena NMVP11 2925, x8.
Diagnosis. See Table 3. Description. Cranidium almost as long as wide, with glabella standing above other areas in anterior view, with smooth surface. Glabella with straight sides or extremely_gently waisted at S2, tapering gently forward to well rounded anterior, with three pairs of incomplete lateral
furrows barely evident and running posteroax ially from axial furrow except for transverse S3 just behind eye ridge. Occipital furrow trans verse, distinct, slightly longer with apodemal pits I aterally then shallowest adj acent to axial furrow. Occipital ring elongate over central part, with prominent medial node near or at posterior mar gin. Preglabellar field upt o twicelength of border
304
STEFAN BENGTSON et al.
Fig. 196. Pararaiabunyerooensis Jell, sp. novo A-C,cranidia. A, NMVP112861, x5. B,112864, x3. C, holotype 112862, x5. D-F, librigenae NMVP112860, 112851,112996, x5. G,cranidium NMVP112866,x5. H,l, dorsal and anterior views of cranidium NMVP112849, x6. J,K, pygidia NMVP112863, 112850, x20. L-O,cranidia. L, NMVP112858, x5. M, 111840, x8. N, 127052, x4. 0, 113124, x7.
in sagittal line, with prominent plectrum narrow ing posteriorly to glabellar anterior. Border fur row generally not well-impressed but distinct except medially as a change of slope on most
specimens. Anterior border gently convex, of uniform length, sloping forward. Genal caecae e vident r unning forward from preglabellar fur row or eye line to cross border furrow into rear
EARLY CAMBRIAN FOSSILS, S. AUST.
305
Table 3. Diagnoses of species ofPararaia� Comparative statements are rel�tive to the previous species (Le. the species to the left). ,
�
P. tatei Cranidium (Length:Width)
L=O.95-0.99W
P. bunyerooensis
P.janeae
L=0.8W
L=O.75W
�
" -
-,
Anterior border
convex uniform length slopes forward
"
Eye line
long prominent
Anterior facial suture
curved
convex uniform length
flat longer laterally upturned,
,
,
"
not as long less prominent
much shorter extends much further laterally
straig�t to B '
straight to B
.
'-
" "
PalpebraJ lobe
thick long
Librigenal border
very wide especially at rear
much thin' short
thinner ,'long ,.
very wide with epiborder furrow
'"
narrow
"
.
much longer still, narrower base
extremely short' and wide
much longer ' broad based
Pygidium
small
more transverse
' stron
Pygidial axis' ,
to posterior margin
not reaching margin
not teaching margin
Marginal spines
2 pairs
3 pairs
Genal spine
.
-
3 pairs "
of border. Eye ridges robust, leaving axial furrow near rear of frontal lobe to curve gently posterior ly into palpebral lobe, the curve becoming stronger through posterior of palpebral lobe, posterior of palpebral lobe, less than basal glabel lar width from axial furrow (Le. interocular cheeks relatively narrow). Palpebral lobe wide, convex i n transverse section, situated with posterior at border furrow on same level as oc cipital furrow and anterior level with L3. Facial suture diverging forward from palpebral lobe in short anteriorly concave curve of anterior limb over short distance to margin; running posterior ly to margin almostexsagittally from rear of palpebral lobe. Posterior border furrow well-im pressed, longer than short border that becomes longer abaxial to the articulating point then dis appears to end of posterior cephalic limb that does not extend laterally as far as palpebral lobe. Librigena small but wide, relatively flat, with broad shallow border furrow near midwidth anteriorly but curving adaxially into posterior border furrow at rear of eye to leave extremely wide border at posterior. Low eye-socle present. Genal field small and narrow, with some sugges-
tion of genal caecae crossing it at right angle� to border furrow. Border wide, and flat to w�akly convex, with fine irregular comarginal terrace lines, with short markedly tapering genal spine. Anterior sutural margin concave. Pygidium tiny and strongly convex '(margin generally downturned strongly); broad axis oc cupying most of it, extending to posterior margin and incorporating at least two segments. Pleural areas with two segments, each ending in short posteriorly directed marginal spine, each crossed by distinct pleural furrow and separated by inter pleural furrow. Pararaia sp. cf. P. tatei (Woodward,1884) (Fig. 194C-E) Material. Cranidium NMVPll1859, and libri gena NMVPll1862 from NMVPL1584, Wil lochta, Parara Lst. Discussion. This material occurs with typical P. tatei but the lack of a:n anterior border furrow, parallel- sided glabella, and longer genal spine make assignment to that species difficult. The
306
STEFAN BENGTSON eta/. .
differences may be expressions of wide variation of spine around to facial suture. Terrace lines are within P. tatei but until a wider selection of . riot evident but a strong transverse caecal ridge material is examined it is necessary to isolate this parallels the posterior margin away. from the materiaf specifically. . facial suture. One specimen (Fig.196F) is ap parently compressed leaving a marked ridge around margin even into genal spine that probab Pararaia bunyerooensis Jell,sp·. novo (Fig. 196) . ly represents a respiratory caecum (Jell, 1978). Anterior sutural margin straight,except near ·Etymology. For Bunyeroo Creek. cephalic margin where it curves strongly forward to leave strong pointed anterior. Material. HolotypeNMVP112862 fromNMV Pygidium tiny and convex;·· PL1593. Paratypes NMVPl12849,112851, c.1/2 sUrface area,with posterior not reaching 112856-112861,)12863-112866 from NMV margin but defined by shallow distinct axial fur-, PLl593,Wilkawillina Gorge,Parara Lst. Other row that is above steep descent to border. Pleural m a t e r i a l. NMVP 113123 - 1 13125 from areas not so clearly segmented except for NMVPL99,Bunyeroo Creek, Parara LSt.; anterior one and with three . pairs. of tiny horizonNMVP127052 from NMVPL1513,Wilkawilli tal marginal spines. na Gorge,Parara Lst Pararaiajaneae Jell,sp. novo (Fig.197) Diagnosis. See Table 3. Etymology. For Jane Jell who helped collect Description. This species is described only Flinders Ranges trilobites over 5 field trips. where it differs from P. tatei and all comparisons . mentioned are with that species. Material. H o l o t yp e NMV Pl13 2 4 8 from Cranidial.length 4/5 width,with glabella not NMVPL1590, Bunyeroo Creek,Oraparinna quite as highcfbove cheeks. "Glabella with lateral Shale. Par atypes NMVP111888, 113212, furrows slightly better impressed, and extending 111854, 113287,113218,111873,111877, further towards the axis. Occipital ring more 1132S4, 113266,113267,113186,113242, 113248,113264 fromNMVPLI590,Bunyeroo uniform in length (Le. the lateral parts are more Creek,Oraparinna Shale. Other ma�\.-rial elongate). Preglabellar field a little longer than border sagittally. Border furrow indistinct, large NMVP 112823 from NMVPL80 Bunyeroo ly defined by change of slope;· border flat, Gorge,Oraparinna Sbale;NMVPI12732, downsloping, becoming slightly longer laterally.. 112733, 112744,112751,112753,112755, 1 1 2 7 6 0 ,112818--112820 ,11:31 5 5 f r om Width of interocular cheek plus palpebral lobe C. 1.3 times basal width. of glabella. Eye lines NMVPL1588 Bunyeroo Creek,Oraparinna Shale; NMVP111850,111874-111876,111879, shorter than in P. tatei. Anterior part of facial 111888,113168,113171,113173, 113174, suture diverging but straight to B at about middle 113177, 113180,113181,113189,113193, of border then curving strongly adaxially so leav 113195,113196,113198,113217,113223, ing pointed anterior on librigena. Posterior 113231,113233,113139,113241,113247, c�phalic limb e�tending only just beyond . greatest lateral extent of palpebral lobe and being 113250- 113252,113254,113261, 1132771 13279,113281, 1 1 3285,113289 from . a little longer at the extremity than it is in P. tatei. . Librigena with border furrow well away from NMVPL1590,Bunyeroo Creek,Oraparinna margin near midwidth,running. around genal Shale;NMVP127044-127046 from NMVPL · angle parallel to ocular ma rgin then into 1599,Wirrealpa Springs, post�rior border furrow.On outer part of border near margin is a broad but deep epiborder furrow Diagnosis. See Table 3. that fades out down the genal spine. Genal spine Description. Cranidial length C. 0.75 of width, longer and less tapered than in P. tateibut retain ing broad base and even curve from inner edge with glabella sunken slightly between cheeks, .
.
Fig. 197. Pararaia j(meae Je l l sp. nov. C,F,G,L,M, externals, I 1atex cast, others partially exfoHated or internal casts. A-E� cranidia. A, NMVP111888, x2. B, 113212, x5. C, 113155, x6. D, 111854, x5. E, 113287, x3. F, pygidium NMVPl12744, x8. G, pygidium NMVP111850, xl1. H, pygidial fragment NMVP113218, x8. I-K, cranidia. I, NMVPll1873, x4. J, 111877, x8. K, 113284, x8. L,M, 1ibrigenae NMVP113267, 113266, x5. N, ventral view of rostral plate NMVP11 3186, x6. 0, thoracic pleura NMVP113242, x6. P, holotype cranidium . NMVP113248;" x3. Q, cranidium NMVPl13264, x3. ,
EARLY CAMBRIAN FOSSILS, S. AUST.
307
308
STEFAN BENGTSON.
et
al.
surface smooth but in largest.specimens becom ing finely ' p r e s s e d. f u r r o w s , S 1 .a n d S2 a p pa r e n t l y continuous across axis in some, usually larger individuals,with anterior narrowly rounded. Oc cipital ring running across axial furrow as a low ridge into posteroproximal corner of fixed cheek, with apodemal pits gener�lly more obvious than in other species. Preglabellar field quite long, 2-3 times length of border" with plectrum of uniform widt� less prominent and tending to appear more as a central boss in sonie in dividuals, with prominent caecal development running ftom anterior trunk of eye ridge forward across border furrow into border. Border furrow well impressed,long and of uniform length,with broadly rounded cross-section. Anterior border strongly upturned,to margin, of uniform length. Several specimens show a low ridge in the anterior .half of the bord�r furrow with genal caeca running into but not beyond it. Eye ridges transverse or nearly so, curving a . little to the posterior abaxially, short near axial furrow be coming longer near palpebra] lobe,composed of two main trunks. Palpebral lobes relatively nar row,flat in transverse section, upturned abaxial ly, relatively'short and strongly curved to be elongate kidney-shaped, with posterior situated at level of anterior of L1 rather than SO. Facial suture diverging forward strdngly from anterior of palpebral lobe in an almost straight .line to outer part of border where it turns sharply in a rounded corner to the anterior ,margin. Posterior cephalic limb extending a short distance lateral to palpebral lobe. Posterior bordeT furrow well impressed, running slightly forward and becom ing longer laterally.. Posterior border short and rim-like.
of border adaxial of. whiCh it sl�pes stro.ngly dorsally with its upturned part running' across base of genal spine. Pygidium strongly transverse (twice as wide as long), low and flat, occupying nearly half total width but not quite reaching posterior margin, with only one ring furrow, evident a short dis tance behind the deep articulating furrow ':and incipient suggestion of the next posterior ring furrow. Articulating half ring crescentic,sho,rter than first ring. Axial furrow not impressed,mar gins of axis indistinct, defined by origins of pleural furrows. Pleural areas including three segments separated by cleft-like interpleural fur rows and with two anterior segments bearing pleural furrows similar to the interpleural fur rows but running diagonally from near anterior at axial furrow to midlength marginally so that posterior pleural band is of uniform length; three pairs (and possibly four in larger individuals) '.of short marginal spines directed posteriorly. \
Alanisia Hupe,1953 Type species. Camaraspis guillermoi Richter R. & Richter E.,1940 from the Early Cambrian Saukianda-Stufe near Alanis, Spain;'by original designation.
Discussion. Two species were originally recog nized (Richter & Richter, 1940) as belonging to this genus but Henningsmoen (1958) considered the two morphologies to represent different tec tonical1y induced forms of the same species. Sdzuy (1961) confirmed Henningsmoen's inter pretation and indicated the same range of mor phologies i n A. hastata Sdzuy,1958. The material from NMVPL96 in the Kulpara Road Rostral plate short, of uniform length, wide section exhibits the same tectonically induced (probably as wide as anterior border on cranidrange of morphologies; as with A. hastata the differences are most noticeable where the sagit ium), terminating lateral1y in connectiye sutures normal to the edges of curved rostral plate. tal axes of two adjacent cranidia are normal to Ventral surface with a stroilg comarginal ridge at each other (cf Sdzuy,1961, pl.14, fig� 1 and, Fig. the change of slope where the surface is strongly 198C). upturned towards the posterior. Alanisia has been assigned to the Antatlasiidae (Hupe,1953) and the Ellipsocephalidae (Sdzuy, Librigena with genal field occupying half 1961) but glabellar shape, preglabellar field and, width,with broad border furrow cutting off genal palpebral structures a re suggestive of t he angle as it swings adaxially posteriorly close to Protolenidae. Moreover, the close similarity in the ocular margin. Wide border gently upturned, flatter to posterior, with shallow epiborder furthese features to Pararaia Kobayashi, 1942 sug gest that they belong to the same family and the row on outer half running down genal spine and matched by another shallow furrow on adaxial latter seems most appropriately assigned to the side of genal spine running into posterior border .. Protolenidae. Alueva Sdzuy,1961 from the Early Cambrian of Spai� is very similar to Alanisia furrow close to rear m' as rest of librigena, broad.1y based; ,tapering with which ,it may prove to be synonymous; strongly near base, less'so distally. Doublure transfer of A. hastata to Alueva by Lifian & Gonzalo (1986, p.48) further suggests this extending adaxiaIly to border furrow, of uniform synonymy, with Alanisia having priority. width, with sharp line of inflection near middle
EARLY CAMBRIAN FOSSILS, S. AUST.
309
Alanisia guillermoi (Richter R. & Riehter E., 1940) (Figs 198, 199J-N)
moulds; anterior border short, flat to gently con vex, of uniform'length- and section. Eyeline leav ing' axial furrow behind anterior of glabella, 1940 Camaraspis guillermoi Richter R. & Richter running posterolaterally at <100 to transverse, ' E., pA4, p1.3, figs 64-67. turning sharply back' at anterior of' palpebral 1940 Camaraspis onyx Richter R. & Richter E., lobe; palpebral lobe short, gently arcuate, flat to pA6, p1.3, figs 68-73. laterally downsloping, situated with its midAlanisia guillermoi(Richter & Richter); Hupe, length near the midlength of the glabella, defjned 1953 p.207, 233, fig.56-10. by well-impressed palpebral furrow that curves , 1958 Alanisia guillermoi(Richter & Riehter); Hen- laterally around rear of lobe. Posterior cephalic ningsmoen, p. �66. limb long but narrow, extending barely beyond' 1975b Bigotina tina Opik, pAO, pl.7, fig. I. palpebral lobe laterally. Posterior border furrow well impressed, running slightly forward and' Material. Holotype Se nckenberg Museum shallowing laterally, particularly beyond lateral Xl143a from near Alanis, southern Spain, in the - articulating point where it descerids. Surface of Lower Cambrian Alanis Shale. Australian cranidium, except furrows, covered'by ornament' material NMVP103441-103443, 103446 from of fine pustules, ornament not evident on internal NMVPL 73, Kul para, Parara Lst.; NMVP moulds. Librigena smooth, with wide indistinct· 112599-112617, 112620-112623, 112625border bearing comarginal terrace 'lines near' 112630, 112632, 112633, 112635, 112637, margin and contiriuing onto stout genal spine. 112639 from NMVPL96, Kulpara, Parara Lst.; NMVP103499 from the F. Chapman Collection Remarks. Affinities have been discussed above labelled 'Ptychoparia c f . tatei (H. Wood. ), and assignment ' of, Australian material to the: Cambrian, Kulpara, Sth Aust. pres. A.W. European species is 'based on close comparison Kleeman 6/33' in Chapman's own handwriting. with the originally illustrated material of Richter This specimen may be confidently' assumed to & Richter (1940). Material illustrated includes �.ome from the same collection as the holotype of cranidia identical with the'ir A. onyx (Fig� Opik's (1975b) Bigotina tina. 198C(upper),J,K) and with their, A. guillermoi (Fig. 198C(lower),F, 199M) which synonymy of Diagnosis. Member of Alanisia with strong oc Henningsmoen (1958) is accepted herein.' Gla-' e
cipital spine.
Description. Cranidium broadly convex, with glabella standing above relatively flat fixigenae in anterior profile; lateral profile from flat anterior border rising steeply up preglabellar field and anterior of glabella then flattening out before occipital spine rises steeply at rear. Glabella 3/4 of cephalic length, relatively nar:.. row,just over 1/5 of cephalic width; with straight sides tapering gentlyforward to rounded anterior some distance from border furrow (and 1 /4 of cephalic length from anterior margin); three pairs of lateral glabellarfurrows barely evident on exterior of exoskeleton but distinct on internal moulds, becoming more transverse and narrower anteriorly, with anterior pair just behind proximal end of the eyeline; occipital ring slight ly elongate medially and bearing short steeply rising occipital spine, with prominent terrace lines running along the spine parallel to margin. Axial furrow weakly impressed laterally but not impressed anteriorly where it is defined only by a minor change of slope. Preglabellar field usual ly flat but often gentJy inflated as insignificant bulge sometimes extending across border furrow and giving' t he impression of a wide low plectrum. Anterior border furrow weakly im pressed but deeply impressed on internal
bellar shape, preglabellar structure, nature of the, border, palpebro-ocular structure and the occipi tal spine are all identical and no distindions are evident that are not most reasonably- attributed to tectonic distortion." Marked differences are apparent between the external exoskeletal.. surface (Fig.198M) and the internal mould (Opik, 1975b, pl.7, fig.l; Fig.198L). In the latter, all-furrows seem much better impressed, particularly the border and pal pebral furrows, the occipital spine is not general ly evident becaus� it is so strongly directed dorsally that it breaks off as part of the external mould, the anterolateral corriers of the glabella seem more angular and there is a small sIlver of flat mould outside the anterior of the palpebral lobe that presumably represents a structure on the inner surface of the exoskeleton but not on the outer. This last feature is not evident on illustra tions of Richter & Richter but they have been retouched or cut out and the very slim expression' of it may have been destroyed or aJtematively it could be variation between populations; it is certainly not indicative of separate species. Intraspecific variation is evident in the' anterior glabellar shape, degree of impression of the oc cipital furrow and incipient development of a subtle boss on the preglabellar field.'
310
STEFANBENGTSON etal.
Family ICHANGIIDAE Zhu, 1980 brik (1975b) characterized the Ellipsocepha100dea as trilobites without or with very narrow posterolateral cephalic limbs and with eye lines and palpebral lobes that ran into each other without differentiation. Within the Protolenidae of this superfamily Zhu (in Zhang W.T. et al., 1980) erect�d the Ichangiinae for a group of Chinese genera with glabella slightly expanded between proximal ends of eye ridge, short posterior sections of facial sutures, genal spine stout long and advanced, 13 thoracic segments and transverse pygidium wi� 2-3 pairs of mar ginal spines. However, as Opik (1975b, pol2) noted, the Protolenidae have conical glabellae so excluding the Ichangiinae; I prefer to regard Zhu's grouping as a separate family with the same distinguishin&.characters. Whereas I accept Opik's (1975b) suggestion of a lineage from the ElIipsocephaloidea through Hswspis Z h a n g , 1 9 5 7 (=Estaingia Pocock, 1964) toXystriduridae I donot accept the group ing oftheXystriduridae with the Paradoxididae. I suggest the Paradoxididae arose from the Siberian group 0 fgenera includingParam icma c ca, Bergeroniellus, 8ergeroniaspis and Lermon tovia. The resemblance between Paradoxididae and Xystriduridae is the result of contem poraneous homeomorphy; the clue to lineage identities is in the pygidial structures where the Northern Hemisphere forms arc narrow, almost subquadrate in the beginning of the lineage and the Australian- Chinese group is morc trans verse. I suggest that these two families should be included in the Ellipsocephaloidea as end mem bers of separate lineages along with the Early Cambrian Ichangiidae, Protolenidaeand ElIipsocephalidae at least. _ Note t�.at Strenax Opik,1975b based on S. cerastes Opik,1975b from western N.S.W. may be regarded a s a junior subjective synonym ofthe ichangiid Pseudichangia Chu & Zhou in Lu el al. ,1974 from southwestern China whieh may explain why its pygidium was not distinguished from that of 'Estaingia bilobata' occurring at the same site in N.S.W. - they are too similar to be separated. Hsuaspis Zhang,1957 1957
HsuaspisZhang,p.14S.
1964
Estaingia Pocock, p. 4 62.
1965 Hsuaspis Zhang; Zhang in LUer at., p.8S. 1975b Estaingia Pocock; Opik, p.lO. 1980
Hsuaspis Zhang; Zhu in ZhangW.T.eral., p.244.
1980
Zhuxiella Zhang&Zhu in Zhang W.T. e t a i., p.247.
Type species. Lusatiops sinensis Zhang,1953 from the Early Cambrian of southwestern Cbina; by on'ginal designation. Discussion. Comparison of cephala of H. sinen si! (Zhu in Zhang W.T. et 0/.,1980, p1.79, figs 6,7) andEstaingia bilobata Pocock (1964,pI.75,
fig.l; p1.76, fig.5), the type species of Estaingia Pocock, 1964 from Early Cambrian of Kangaroo Island, South Australia, reveals no differences except for the glabella reaching a little further forward and the genal spine being advanced in the former. In the pygidium H. sinensishas three segments and three pairs of marginal spines whercasE. bilobata has only two pairs of spines and an incipient third pair (Pocock,1964, text fig.3}- In the illustration available (Zhu in Zhang W.T. et al.,1980, pl.79, fig.8) the anterior pygidial segment is defined by a distinct inter pleural furrow, a more distinct furrow than that between segments two and three. This may indi cate that it w as about to move out into the thorax in which case it would be a meraspid pygidium and the holaspid may have two pairs of marginal spines. A larger collection of pygidia will be necessary to establish this point but in any event the two species have such similar pygidia in those parts that are comparable. Whereas Pocock (1964, p.467) quoted E. bilobala as having 12 thoracic segments his illustration of theholotype (Pocock, 1964, pl.75, fig. 1) exhibits 13 thoracic segments bringing it into line with the family diagnosis. Estaingia is considered a junior sub jective synonym ofHsuaspisand the new species described below with a small occipital spine may be the link to some of the other occipital spine bearing genera of the family like khangia Zhang, 1957 or Pseudichangia Chu & Zhou in Lu et 0/.,1974. Also Zlruxiella Zhang & Zhu in Zhang W.T. et al.,1980 based on Z. lrubeiensis Zhang & Zhu in Zhang W .T. et al.,1 980 from the Early Cambrian of Hubei may be distinguished at species level on the characters quoted by Zhang & Zhu (in Zhang et 0/.,1980, p.433) but at generic level it should be regarded as a junior subjective synonym ofHsuaspis.
Fig. 198. Alanisia guillermoi (Ricbter, R & Richter, E.,1940). AB , , NMVP103442, x3. C, two cranidia NMVPll 2620, x4 (upp er) and NMVP112621, x4. D,E, dorsal and anterolateral views of cranidium NMVP112603, x2 . F-H, cranidia NMVP112 627, xJ; 1 12633, x3.5; 112628, x3 . I,M, ante rior and dorsal views of cranidium NMVP112606, x3. J-L, cranidia NMVP112613, x4; 112637, x3; 103499, x4. N, librigena NMVP112614, x6.
EARLY CAMBRIAN FOSSILS, S. AUST.
311
312
STEFANBENGTSON etal.
Hsuaspis bilobata (Po cock, 1964) (Fig.199A
to glabella then gently convex flattening out to curve along glabella. Glabella wider than each interocular cheek, just less than 1/2 cranidial 1964 Estaingia bilobala Pocock, p.463, pis 75,76. width, parallel-sided, slightly waisted at L2, with ?1975b Estoingia bilobala Pocock; Opik, p.ll, pl.l rounded anterior having subtle straightening on either side ahead of eye lilies, finishing well back Material. HoIotype AUGDF16441. Paratypes from anterior border furrow; lateral glabe llar fur AUGDF16442·-16550. Other material assigned rows extremely faint, transverse, S3 fainter than NMVP112756, 112757, 112770, 113158. others, separating lobes of uniform length but 113288 from NMVPL1588 and NMVP112699. with frontal lobe twice as long as any other; 112808 from NMVPL1589 Bunyeroo Creek,. occipital furrow moderately well impressed, transverse, with slight apodemal pits laterally; Oraparinna Shale; NMVPl12997-113016 from NMVPLl595, Bunyeroo Creek, Oraparinna occipital ring long, tapering laterally, gently con vex in lateral profile, with short slender median S h a l e ; NMV P 1 2 7 0 1 9 , 127020 f r o m spine in horizontal attitude arising from mid NMVPL1596, Kangaroo Island, EmuBay Shale. length of occipital ring and lying on posterior half with extension beyond margin shorter than Remarks. This species was described in ad half occipital length; axial furrow not impressed, mirable detail by its author and my material evident merely as change of slope; preglabellar provides no additional information on its mor field long, downsloping, with low median ridge phology. �pecific identity of the material as signedb y Opik (1975b) from western New South running from just forward of preglabellar furrow into anterior border. Anterior border furrow dis Wales remains equivocal in so faras that material tinct but shallow due to V-shaped cross-section, has a consistently shorter preglabellar field, and interrupted by p r e g l a b e l lar median ridge; slightly advanced genal spine. anterior border much shorter than preglabellar Hsuaspis occipitospina Jell, sp. novo (Fig.200) field, flat, downs loping, tapering laterally. Eye line almost imperceptible, transverse from Etymology. Latin occipuJ, back of the head, posterior of frontal glabe llar lobe; palpebral lobe wide, defined by shallow palpebral furrow, half spina, spine. teardrop-shape d with sharply downtumed outer Material. H o l o t y p e NMVPl12701 f r o m margin, posterior end some distance further from NMVPL87,Wirrealpa, Oraparinna Shale. axis than anterior end; facial sutures diverging Paratypes NMVP112645, 112646, 112648- forward from p alpebral lobe, curving axially 112652,112657, 112659, 112660, 112662, across border, l aterally convex behind eye but 112663,112665, 112667-112670,112672nn extending laterally as far as outer edge of palpebral lobe; posterior border furrow long, 112674, 112676, 112677, 112679-112681, 1 12683-112685. 112687 -112 689,112693, well impressed, becoming more elongate to 112694, 112696-112698, 112700-112702, reach posterior of palpebral lobe laterally; 112703from NMVPL 87, Wirrealpa, Oraparinna posterior border short, gently downsloping Shale. Other material NMV P112845-112848 beyond lateral articulating device. Rostral plate from NMVPLl592,east of Wilkawillina Gorge, strongly convex, extending laterally almost to Oraparinna Shale. facial suture, with strongly geniculate exsagittal section being almost a right angle laterally but rounder sagittally, with irregular comarginal ter Diagnosis. Member of Hsuaspis with axial fur r ace Iines on inner part of flat ventral half, with row evident as change of slope only, relatively long preglabcllar field crossed by preglabellar steeply upturned half smooth, with straight rostral suture. Librigena with narrow genal field, median ridge, occipital s�ine; pygidium with anterior marginal spine Widely separated from extremely shallow border furrow, wide flat bor posterior one. der; long, slightly advanced genal spine running posterolaterally and not continuing even cUlve of Description. Cranidium slightly wider than long, gently convex in anterior profile with cephalic margin; doublure with well-developed glabella more convex, standing above the other comarginal terrace lines on flat ventral section wise even curve; lateral profile with flat slope up and extending well down length of genal spine, I)
Fig. 199. A-I, HSJUlSpis bilobata (Pocock,1964). A-E, cranidia NMVP112770, x6; 113016, x6; 112756, x8; 113004, x6; 113158, xl0. F-H, librigenae NMVP112808, 113288, 112699, x8. J, articulated i ndividual NMVPIZ7019, x4. J-N, Alam'siaguillermoi(Richter, R. & Richter, E., 1940) cranidiaJ,K. NMVP112615, x4 (J,K, dOlsal and anterior obliqueviews); L, 112629, x4; M, 112625, x4; N, 103441, x4.
EARLY CAMBRIAN FOSSILS, S. AUST.
313
314
STEFAN BENGTSON eta!'
with sharply upturned inner section continuing flange from rostral plate and giving geniculate cross-section normal to margin; ridge along the geniculation continuing onto basal part of genal spine. Hypostome unknown Thoracic segments with pleurae of variable lengths; wider the pleura shorter the half ring; half ring may be longer than articulating ring in those with narrowest pleurae; articulating ring flat in exsagittal section, with low median tubercle on most specimens; pleural furrow well impressed remaining closer to anterior margin throughout and deepest just beyond articulating line close behind articulatin g facet, with steeper anterior than posterior wall; free pleura with large flat facet anteriorly, tapering spinose laterally directed tip, others with rounded trun cated tip and furrow finishing against exsagittal margin with slight tip at posterolateral corner; smooth except for granulose ornament on elevated portions of free pleurae. Pygidium transverse, more than twice as wide as long, strongly convex in lateral profile with lateral andposterior border strongly down turned, similarly convex in posterior profile with axis flattish on to pand higher than pleural areas, axis broad, parallel-sided, posteriorly rounded, finishing at posterior border furrow, poorly seg mented with two anterior segments barely evi dent and large bilobed terminus; pleural areas well segmented with two anterior segments with pleural and interpleural fUlrows; anterior pleural band offirst segment much shorter thanposten'OJ band, with wide anteriorly sloping facet but ex tending laterally beyond the facet in sharp posteriorly directed spine; second segment also with shorter antcrior pleural bandandposteriorly directed marginal spine at tip but spine more evenly situated as emanating from both pleural bands; pleural areas with fine granulose orna ment except in furrows; a poorly defined almost vertical border area encircling rear of axis. Morplwgeny. A series of cranidia 0.3-20mm long is available with the smallest probably an early meraspid with one or two segments. Al though uncertain as to size of earliest holaspid it appears that at least the three smallest cranidia (Fig.2ooB-D) are probably meraspides. The glabella gradually withdraws from the anterior border and border furrow, The anteriorly trun-
cated glabella becomes more rounded and the widest point moves backalong thefrontalglabel lar lobe to behind its midlength. The occipital ring becomes relatively shorter with growth. Length to width ratio of cranidium appears 10 increase with growth but this may be due to flattening during compaction as it is not consis tent. The occipital spine appears at an early stage (Fig.200A.C). Remarks. This species is readily distinguished from H. bilobata on its occipital spine, more effaced ce phalon, posterolatera Ily directed genal spines, less obvious eye lincs, slightly more anterior posterior tip of palpebral lobe, larger pygidial axis and more laterally situated anterior pygidial marginal spine. Order CORYNEXOCHIDA Family ZACANTHOIDIDAE Swinnerton,1915 Micmaccopsis Lermontova,1940 1940
MicmaccopsisLermontova, p. 133.
\951
MicmoccopsisI.ermontova; T.ennontova, p.84.
1964
Micmaccopsis I.ermontova; Suvorova, p.26.
1974
MicmaccopsisI.e rmontova; Repina el al., p.155.
Type species. Micmaccopsis redliclwides Ler montova,1940 from the Botoma Stage (Sinsk or Olekminsk Gorizonts) on the Siberian Platform; by original designation. Micmaccopsis separala Jell, sp. novo (Fig.201 A,B,D,E,J,J,M) Etymology. Latinseparatus, separated; referring 10 the bilobed pygidial terminus. Material. Holotype NMVPl13324. Paratypes NMVP103475, 112881. Other material 103474. 103492, 112884, 113325, and 127159. All from NMVPL1499 except 103475 and 103492 from NMVPLtOO, both localities near Wirrealpa Mine, Wilkawillina Lst. Diagnosis. Large convex trilobite with finely tuberculate ornament. Glabella with straight parallel sidcs and broadly rounded antcn'or; S l and S 2 barely evident. Short ocCipital spine sharply pointed. Preglabellar field short,
Fig. 200. Ilsuaspis ocdpitospina Jell, sp. novo A_D,juvenile cranidia in descending size range NMVP112700, 112685, 112694, 112677, C. )(25. E,F, large cranidium (F latex cast)NMVP112701, ...2.5 and x2, respectively.
G,H, small cranidia NMVP l12683, ...7; 112657, ... 9.1,1, partial thoracic segments NMVP112674, 112648, ...3. K,L, pygidia NMVP112659. x7; 112698,x3, M, Iibrigena NMVP1l2702, ...3. N, cranidium NMVPl12845,... 7. O,R, anterolateral and dorsa! views of cranidium NMVPI12667, x4.5. P ,Q, anterolateral and dorsal views of cranidium NMVP112846, x6. S, cranidium NMVPl12687, x5.
EARL Y CAMBRIAN FOSSILS, S. AUST.
315
316
STEFAN BENGTSON et al.
depressed, with weak plectrum. Fixigena small anteriorly and narrow between eyes. Palpebral lobes long, narrow, flat to laterally upturned and defined by well-impressed palpebral furrow. Posterior cephalic limb with short spine laterally. Description. Cranidium upto 20mm long, with axis gently convex above flat interocular cheeks in anterior profile, with strongly convex glabellar anterior standing above weakly convex anterior border and leading to upturned occipital spine in lateral profile. Glabella occupying majority of cranidial area, with straight parallel sides, with broadly rounded anterior reaching close to anterior border furrow. Glabellar furrows weak; SI e v i d e nt at axial f u rrow then runni n g posteroaxially before being extremely shallow across axis; S2 barely evident as shallow furrow parallel to Sl so that L1 and L2 are of equal length. Occipital furrow long and shallow, with deep apodemal pits at the axial furrow and with the fine tuberculate ornament aligned into transverse ridges within the furrow. Occipital spine short, rising steeply, and sharply pointed. Preglabe\lar field short, depressed. Border subtly elongate medially as small inconspicuous plectrum extending back into the preglabellar field. Anterior part of fixigena small, with anterior section of facial suture leaving eye line close to axial furrow and curving anteriorly al most immediately to be exsagittal across border. Interocular cheeks each c. 1/4 of glabellar width, gently convex" widest opposite L2. Palpebral lobe uniformly narrow, gently arcuate, sloping up laterally, running anteriorly to outer edge of axial furrow where it turns anteriorly but does not cross furrow, finishing posteriorly near mid length of LI well away from axial furrow; pal pebral furrow shallow anteriorly but wider and deeper than axial furrow for remainder, curving down and laterally around posterior of lobe. Posterior cephalic limb wide, extremely short, with short posteriorly directed spine at lateral extent. Pygidium transverse; axis a little more than half total width. Axis of two well-defined rings and longer bilobed terminus extending close to excavated posterior margin. Pleural area of three segments with short marginal spine on each be coming progressively smaller to posterior; pleural and interpleural furrows becoming less evident posteriorly and fading out laterally on
wide border area; pleural furrow in midlength at axial furrow but at margin anterior pleural band occupies entire segmental length; posterior pleural band of each segment crosses axial fur row into posterolateral corner-of axial ring. Over all shape subquadrate with first marginal spine posterior to rear of axis. Ornament of fine tubercles most prominent on axial rings and anterior of pleural areas, becoming finer to posterior. Ornament of fine widely spaced rarely aligned tubercles over whole exoskeleton except in axial, palpebral, and glabellar furrows on cranidium and on articulating half ring in pygidium. Remarks. This species may be distinguished from M. alba sp. novo by its extremely weak development of a plectrum, by its narrower in terocular cheeks, by the course of the anterior part of the facial suture, by the slightly coarser ornament that may become aligned in the occipi tal furrow, by its suboval pygidium and by the strongly bilobed axial terminus. The possibility should not be discounted thatM. separata and M. alba represent end members of a single species but on the available material it seems more likely that two species are represented. It is distin guished from Siberian species (Suvorova,l964) by its narrower interocular cheek, shorter occipi tal spine and course of the anterior part of the facial suture.. Assignment of pygidia to these two Australian species of Micmaccopsis is questionable but for the present the more coarsely granular is as signed to M. separata; no confirmation of this choice is available at present. Moreover, assign ment of librigena betweenXela drena and the co occurring species of Micmaccopsis is ques tionable. Some of the smaller more convex librigenae may well belong to Micmaccopsis but at present I am unable to distinguish between the librigenae of the three species; I have tentatively assigned all the tuberculate librigenae from this locality to X. drena as a preliminary step. Micmaccopsis alba Jell, sp. novo (Fig.20lC,F, G,H,K,L) Etymology. Latin alba, white; for the colour of the limestone. Material. Holotype NMVP127076. Paratype
Fig. 201. A,B,D,E,I,J,M, Micmaccopsisseparata Jell, sp. novo A, immature cranidium NMVP103492, x10. B, part of posterior thoracic segment NMVP103474, x3. D,E, pygidia NMVP127159, 113325, x3. I,J, dorsal and anterior views of cranidium NMVP103475, x5. M, holotype cranidium NMVPl13324, x3. C,F,G,H,K,L, MicmaccopsisaLba Jell, sp. novo C,F, pygidia NMVP103479, 127160, x3. G,H, latex cast and external surface of holotype cranidium NMVP127076. x5. K,L. anterolateral and dorsal views of cranidium NMVP103482, x4.
EARLY CAMBRIAN FOSSILS, S. AUST.
317
318
STEFAN BENGTSON et al.
NMVPI03482. Other material NMVPl13321, 103479, 127160. All from NMVP1499 except NMVPI03482 from NMVPLlOO, both localities near Wirrealpa Mine, WilkawiUina Lst.
1959 Paleofossus Pokrovskaya, p.131.
Diagnosis. M em b e r o f Micmaccopsis w i t h strong plectrum, with para frontal band running into plectrum, with relatively wide interocular cheeks and poorly impressed glabellar furrows. Pygidium with axis of two rings and bilobed terminus, with two pairs of small marginal spines at ends of two segments in each large pleural area.
Type species. Paleofossus zaicevi Pokrovskaya, 1959 from the Early Cambrian Botoma Stage (Sanashtygol Gorizont) in Tuva, southern USSR.
Description. This species is described only where it differs from or is compared with M. separatus. Glabella less broadly rounded, with S1 extremely shallow but continuous across axis; preglabeUar field apparently becoming longer with growth, with strong short pl ectrum; parafrontal band present with at least three branches running from it across the fixed cheek to border furrow, one of these leaving eye line where it meets axial furrow; anterior border elon gate medially, particularly across plectrum, with ornament of fine terrace lines near margin ap parently made of aligned granules and sub parallel to margin. PaJpebral lobes more strongly arcuate with interocular cheeks occupying 1/2 glabellar width, lobe upturned laterally and un ornamented. Anterior part of facial suture almost straight at 45° to exsagittal line, curving across anterior half of border. Ornament of granules over entire cranidium tending to be aligned into subparallel ridges in some areas, not evident in furrows. Pygidium with strongly bilobed axial terminus finishing well in front of posterior margin that is not excavated. Pleural areas each with three seg ments and each segment with marginal spine at posterolate r a l tip becoming progressively smaller to posterior. Overall shape suboval with widest point at about level of second ring furrow and first marginal spine at about midlength of terminus. Ornament of fine granules everywhere except in ring furrows on axis. Remarks. This species is distinctive in its plectrum, parafrontal band, and pygidium. Suf ficient material is not available to assess in traspecific variation. One pygidium (Fig. 201E) appears to be aberrant on the right pleural area in the second segment where the pleural furrow does not follow the normal course but rather forks halfway to the margin.
1960 Paleofossus Pokrovskaya; Khalfin, p.190. 1964 Paleofossus Pokrovskaya; Repina in Repina et
al., p.297.
Paleofossus (?) sp. (Fig.202M-P)
Material. NMVP111883, 111884 , 113221, 113275, 113280, 113283 all cranidial fragments from NMVPLl590, Bunyeroo Creek, Oraparin na Shale. Description. Large cranidium probably 3-4cm long; glabella gently convex, with extremely well-impressed lateral furrows, with SI running posteroaxially from the axial furrow and having deeper apodemal pit at axial furrow, with S2 more transverse, straighter and not as deep. In terocular cheek quite wide and exhibiting prominent caecal network. Eye ridge and pal pebral furrow distinctively shaped, almost the shape of a hockey stick with long almost straight section at 45° to exsagittal line and short adaxial hook posteriorly well away from axial furrow and well forward of border furrow; palpebral lobe relatively narrow, upturned laterally, des cending sharply at posterior tip. Posterior cephalic limb long but not particularly wide as facial suture apparently runs to posterior margin at 30-35° to exsagittal line. Remainder of exos keleton unavailable or unrecognized. Remarks. This material is extremely fragmentary and tentatively identified. Paleofossus is sug gested by the shape and attitude of the paJpebro ocular ridge, the depth and shape of SI and the ornament. The style of glabellar furrow distin guishes the other member of the family, Edelsleinaspis Lermontova,1940. Pygidia of Edelsteinaspidae are distinctive but none has been found at this locality. The extremely tenta tive identification is the best available at present. Family JAKUTIDAE Ptouktaspis Repina in Khomentovsky & Repina,1965 1965
Uklaspis (Prouktaspis) Repina in Khomen tovsky & Repina, p.147.
1969
Uktaspis Repina; Egorova in Egorova & Savitsky, p.153 [partim. u. ? insolens and
Family EDELSTEINASPIDAE J 974 Paleofossus Pokrovskaya,1959
U. fortis only). Uktaspis (Prouktaspis) Repina; Repina et al., p.149.
""ilLY CA'.I8RIAN POSSIl5. S. AUST.
P.....ua..QCCil ....... SU'Of(> Early ClUnbrion A.-..ian Stogc 01\ lhe middle re...... of lhe: R've. lea&. Slbe,1.L
T'/p
Va,1 \160.
P. uij',;hen
�Thcdlapcn;' pn>Yid
anmosty '" Kepi.... 1965. thi� luOll U I subgen... iooppamIIly ill companspiJ) ' " U. "fIPU' ID con1,.d.., thoo � -"bl...... lio.... I'D' u.mple, U. /tH1U E,o.o,'o (i. � "SaY;""'1, pl2"i, CIS-Il) frOll! 1IM: Eorly C.mb.i..... Botoma S,,,&", on Ibe Siberion "'"f""" hallle gI>belJI reldlln, lhe bo • cc..... __ of nn.liort in lhe "",",l1li exlc", of lIIe ,"'bell. (Ew:>/o'Il in £&otooto '" S.vi!.ty, 1!i'69, pI.2S. rop 1.3.6.12).then:does appur 10 . "' . occd fOf •mO<e 'i"'.....di."""'io f""adr. _ Oul ll'lal is ou!Side 1IM: seope of 'his P>pc1' witboool """"'" to type m...,.ll. FOf IM lime bei., I r«»inlu the sipiftcanl motpIooIogical dirre",ftCC!; be· IWeu Ihe 'JP" "pc"'.S. U_ 1l"'���'" Ko.· obcw,l%:l rrom IlIe Eo.ly Comb";'. T'fYa G<>rizool. on lb. lIOrdnresIom AIlIW ri.. lad P. ....... Ae<:01'dilllJlyl oeod 10 &l lbella ioforri"ll Lbll ."cirlQIJy vuiabl< ,,·;U.io "''' ,f'CI\O\'t.t;y '" 1\169) .. iporiaS Ilepi-. 1%5) e,=- 01 Pr� """ 16� r. 'nwl_ ....C>lionably to Uu.,>piJ is ....,bot .. puU/ins_"" dKlIlOlnclude P,ed· IDpU ill he, � .,...y.,., myli.. _ "'� .... .. Replna', ,d.,once ID E&<>"""', (m f.coo'<wo '" SuitY.y, 1\169 ...y be ;,"erpmed u lino=>«: of Pr I(� _Lbm.dcniol.
ll'
cated ,Iabell. -tOIICriof teachi", vozy ""- 10 wich ion, .mt"'" �f, wilh "".ocul" c........ �.Ir Il>ltdlotwilD
·
cn:cI:iDJ! i
PTwhall''') (
1\169,
I
i
�
bo
Repi
i
di"""
'1Ic:le"us. won
P....�II<� . I.U J..I, "1'. _. (FiS-202A-L)
£sy-,'&7. ....,;" . 1_. ",bb,",,; ",fem., \0 ilS bopue'."Y Ot;al� iD I trHlt hc:d. M..-:riIIl. lIo1 � NM VP I27II2l. '""1YI''''' I'MVP All (JQm NMV PLlS91. Wilklw,IIi•• GO'lIe. P...... UL f
121(l2I. f2"XrU- 1270l5.
Dacrip inIIIlerior view2nd,"bell. rio.i,.. "eeply rrom 1.lcrior boodcr r.".,... tiw!n del DtfIdinc into ocap".I r"""",.n;:ipib! ",i ne .. laoIonl view. Glabelf. "'lib Slnt"'" Pl••IIoII>dcI. """calc d anICriorl, jll&l bt:b!d tlte bonIct t'Ion_. ,,·ith IDIaior b'S �.,. UmIUiltny from uill r.rmw .nd definilt& I """ lriIII,ultr LI, 52 ........ V..K 10 o nRli sliJ,hrlylorwa.d f""" ui.al furrow.nd short L2, S3 "",,,Iy _ "'nn ng f",,· ward rmm u;.1 f"now jIIII bdriftd .�e 11...; SO ",,�,�JIllll_lott:r:ly ll II .�i" f",· ftIW, occiplll "., ckwt�1C """'i.lly wltCfC � is _ oul i"1O ""'" _I .".... ..... i.1 r",. ,.,.. poo.ly ".IA d p""'••,iorlJ, ....llowin' Iorwa.d.od ..,....-.I o!tl� .. chaoCC of 01""" �nl of eye 1_ with larg< • ..".,. $hall""" r.,.""I:><. Prt&l.lw field'-; ..tr. dt:. rU"",",' diAJ8CI "'ore .. a c-.Iww:. of ' 1 0p< 1" I rUl1O ....d, � will> i,",,,,lo, comorp.... te....... li_ .....""ior 1'1ft4 ct-k (towiCJ Ulc:rioIIy bo.ll .hal""""" .....kodl' boJ"nd mKlkrrctk; ltofdo,:. &"ndJ CIIIIn'U Inlcn· ooir, n."enla, _ p<>SIcrict!y, ....h . "",,"la, """'..li... _ ...... """. ..."".100 . ""_ I i",o'" �ly. wilb ...... _.."..1 ....... probobly sI;ply �. I'J!l:iditmt wittl wide (:\)11>0: am omd ",lotNdy .....u IIat plamtl I/CM; H;'..-id> ..mp; ... Mdts ond _, p;>SICrior. .... ..... �inK bolt ... boo lone artiatllllins I\noot; .", fi� .�ioJ ""11 ..-ell d
defiui"ll:
i
.Iope. 1oItc)
�
I"'*rior ....
u"",", f
IIU.ud ..
by witJ.
320
STEFAN BENGTSON
et
al.
EARLY CAMBRIAN FOSSILS, S. AUST.
3 21
Fig.
203. Kootenia diutina Fritz,1972. A-D, cranidia. A, NMVP113265, x6. B, NMVP112843, x6. C, NMVP111885, x6. 0, NMVP113244, x8. E-L, pygidia. E, NMVP113169, x7. F, NMVP111878, xlO. G, NMVP111881, x5. H, NMVP111872, x4. I, NMVP112835, x6. J, NMVP112827, x8. K, NMVP113288, x7. L, NMVP112835, x6.
side angling slightly posteriorly away from axis; pleural area wide, crossed by at least two almost exsagittal pleural furrows; margin unknown.
Fig.
Surface ornament of fine granules and/or fine ridges over most of elevated surfaces; coarse comarginal ridges on border.
202. A-L, Prouktaspis luta Jell, sp. novo A,B, dorsal and anterolateral views of latex cast of cranidium NMVP127022, x4. c,D, Iibrigenae NMVP127023, x8; 112989, x5. E, cranidium NMVP 112984, x4.5. F,G, dorsal and anterolateral views of cranidium NMVP112971, x4. H,I, cranidia NMVP112990, x7; 112974, x4. J-L, pygidia NMVP112981, x10; 112980, x8; 127025, x5. M-P, Paleofossus (?) sp. cranidial fragments NMVP111883, 111884, 113275, and 113221, x4.
322
STEFAN BENGTSON et al.
Remarks. Although only three cranidia, a libri gena and two pygidia are available and all are damaged or incomplete the glabellar shape, strong occipital spine and palpebral structure are i n dicative of Prouktaspis with the flatter anterior border, virtual lack of preglabellar field, interocular width relating P. luta to P. insolens. However, P. [uta may be distinguished by its better impressed occipital furrow and its posterior border furrow meeting the axial furrow well behind the occipital furrow; its relatively smooth surface further distinguishes it from P. ornata Repina in Khomentovsky & Repina, J 965 from the Atdabanian Stage on the River Botoma, Siberia.
Family DORYPYGIDAE Kootenia Walcott,1889 For synonymy see Fritz (1972, p.35).
Type species. Bathyuriscus (Kootenia) dawsoni Walcott,1889 by original designation. Kootenia diutina Fritz,1972 (Fig.203) 1972 Kootenia diutina Fritz, p.36, pl.2, figs 1-13.
Material. Holotype GSC27216 (Fritz, 1972, p1.2, figs 3-5). Paratypes GSC27215, 27217- 27222 all from the Sekwi Formation of northwestern Canada in sediments ascribed to the Nevadella Zone. Australian material NMVP111872, 111873, 111878, 111881, 111885-11887, 112774, 112827, 112835, 112843, 113169, 113172, 113175, 113176, 113182, 113184, 113187, 113197, 113215, 113235-113237, 113244, 113246, 113253, 113255, 113256, 113260, 113265, 113288, 127050 all from NMVPL1590, Bunyeroo Gorge, Oraparinna Shale. Remarks. The Australian material agrees with Fritz's (1972, p.36) description in all significant details but a few minor variations and different interpretations are noted. Fritz noted three pairs of glabellar furrows but I would interpret the constriction in the anterolateral corners of the glabella as S4 that run forward from the axial furrow continuing the trend of the eyeline. S3 is transverse and SI almost reaches the occipital furrow medially to isolate a pre-occipital basal lobe. Occipital furrow not quite reaching axial furrow but with deep apodemal pits at lateral extremities and with characteristic gentle anterior convexities either side of midline. Pygidial pleural areas are narrower in the
Australian material and the more posterior pleural furrows are less distinct than in the Canadian type specimens.
CRUSTACEANS [SB] Carapaces of bradoriid crustaceans occur in many samples, particularly at Curramulka and Mt. Scott, but only rarely are they well-pre served. UNEL1846 (Curramulka), with at least three bradoriid taxa, is notable. This locality also yields fragments of postero- or anterodorsal spines of a bivalved arthropod apparently similar to Isoxys Walcott, 1890. Such fragments have b e e n i d e n t i f i e d e l s e w h e r e as c o n o d o n t s (,Glauderia' o f Mambetov i n Missarzhevsky & Mambetov,1981). Cambrian bradoriids from Australia were first described from the 'Archaeocyathina Lime stone' at Curramulka (Chapman,1918). Opik (1968, and earlier papers therein), whose ter minology we employ here, Fleming (1973), and Jones & McKenzie ( 1980) extended our knowledge. A c onsiderable literature on Cambrian bradoriids from China, including many Lower Cambrian ones, is also available (Huo,1956,1965; Yinet al.,1980; Li,1975, 1981; H u o & S h u , 1 982,1985; Hou,1 987b; Lin, 1979,1987; Zhang,1987; Cui et al.,1987). Phylum CRUSTACEA Pennant,1977 Class OSTRACODA Latreille,1806 Order BRADORIIDA Raymond,1935 ?Suborder PHOSPHATOCOPINA Muller,1973 F a m i l y M O N A S T E RIID A E Jon e s & McKenzie,1980
Genera. Monasterium Fleming.,1973 (type), Epactridion gen. nov. Diagnosis. Weakly phosphatized carapaces, with anterodorsal tubercles or horns, without distinct marginal rims. Curved ridges extending from anteromedial to posteromedial of valves. Surface reticulate, granular, or pitted. Remarks. Muller (1979) showed that the bra doriid Suborder Phosphatocopina Muller,1964, had a carapace of calcium phosphate, and that the softpart anatomy confirms the unity of the group. Jones & McKenzie (1980) expanded the Bradoriida by including Oepikalutidae and Monasteriidae, giving restricted subordinal diag noses of 'phosphatic shells' (Phosphatocopina) or 'thin chitino-calcareous-phosphatic shells' (Bradoriina). Huo & Shu (1985) subdivided the Bradoriida into the Suborders Abdomina and Lipabdomina, based on the respective presence
EARLY CAMBRIAN FOSSILS, S. AUST.
or absence of a posterior gape. They suggested that the Phosphatocopina may be related to the Lipabdomina, but left the systematic position of the former open. Both lones & McKenzie (1980) and Huo & Shu (198S) regarded the Bradoriida as a polyphyletic association of ancestral ostracodes and phyllocarid-like crustaceans. Epactridion is referred to the Monasteriidae, which lones & McKenzie (1980) and Zhang (1987) regarded as belonging to the Phosphato copina. Its shell, however, appears more pliable than in typical phosphatocopines, and there are certain morphological resemblances to the brad oriine Hipponicharionidae. Consequently, we refer Epactridion and the Monasteriidae only questionably to the Phosphatocopina'.
Epactridion Bengtson, gen. nov, Etymology. From Greek epaktris, skiff, and the diminutive suffix -ion, referring to the boat-like shape of the carapace. The gender is neuter. Type and only species. Epactridion portax Bengtson, sp. novo Distribution. Lower Cambrian, South Australia. Remarks on orientation. Anterior-posterior dis tinction of fossil ostracodes and other bivalved crustaceans can be problematic (Scott,1961). The bradoriid anterior is often determined by a tubercle, interpreted as marking the position of an eye, and the preferred retral swing. Epactri dion, however, lacks tubercles, and by itself direction of swing is not conclusive, because exceptions occur in some phosphatocopines, e.g. . Vestrogothia, where conclusive evidence from preserved soft cuticle shows the widest part to be anterior, probably to accommodate the large labrum (Miiller,1979; Muller found that the pres umed eye lobe in FaWes was not related to any eye). Furthermore, some bradoriids may have a forward swing in early instars (Zepaera rete Fle ming,1973, see lones & McKenzie,1980, fig.S). Paired spines at one end of Epactridion may indicate the posterior. Reasons for a reverse orientation, however, are: 1, the opposite end is the widest, and a retral swing is supposedly most common among bradoriids; 2, the paired spines may be homologous with the 'horns' of Mon asterium (see comparisons below), structures in terpreted as modified eye tubercles. Although tentative, we designate the spine-bearing end of the carapace as anterior. Diagnosis. Anteriorly directed anterodorsal horns close to the margin, lacking connection
323
with antero-posterior curved ridge. Surface pitted, particularly in juveniles. Posterodorsal spike present. Comparisons. The genus is referred to the Monasteriidae on account of its presumed ante rior pair of horns, curved antero-posterior ridge, posterodorsal spike, and lack of marginal rim. It differs from Monasterium in shape and position of horns, apparently reduced calcification and pitted surface pattern. In Monasterium, this pat tern is either reticulate (M. opiki Fleming,1973, M. bucerum Zhang, 1987) or granular (M. dorium Fleming,1973). Comparisons may also be made with Auriculatella Tan (in Yin et al.,1980; Li, 1981; Huo & Shu,198S), which has a distinct curved antero-posterior ridge and pitted surface. Auriculatella has been referred to the Cambri idae Li,197S, a presumed bradoriine family. Epactridion portax Bengtson, sp. nov. (Figs 204-206) Etymology. Greek portax, calf; alluding to the minute anterior pair of horns. Material. Holotype SAMP30922 (Fig. 20S), from VNEL1846, Curramulka, Parara Lst.; 9 paratypes. Diagnosis. As for the genus. Description. The carapace has a straight hinge and semicircular free margin with a slight retral swing, more pronounced in small specimens (cf. Figs 204A and 20SA). In larger specimens a pronounced V-shaped ridge runs parallel to the free margin; a feature only weakly developed in smaller specim ens ( F i g. 2 0 4A-C). Most specimens are laterally compacted, and the sharpness of the ridge is considerably influenced by this compression (Fig.206E). The anterior carries a pair of spines (20-2Sf.Lm long) close to the free margin and just beneath the anterodorsal angle (Figs 204C, 20SG). The spines are directed anteriorly, dorsally, and laterally. A posterodor sal spike c. 15f.Lm long (Fig. 20SA, right) is lacking in the smallest specimen (Fig. 204A,B). There is a tendency towards a posterior gape (Figs 204F, 20SE), but this is not consistent and may be the result of post mortem buckling. The valvts are distinctly pitted with c. 20 pits per 0.1 mm . The pits have a diameter of c. 6 f.Lm and a smooth rounded bottom (Fig. 20SB). The pattern is distinct in smaller specimens (Fig. 204), whereas in larger ones it is more sparse and concentrated near the free margin (Figs 20SD, 206A,E). Range in valve length is 0.41-1.17mm;
324
STEFANBENGTSON etal.
EARLY CAMBRIAN FOSSILS, S. AUST.
325
growth stages characterized by progressive reduction in the surface pitting, increasing dominance of curved ridge, probably also development of a posterodorsal spike and sup pression of the retral swing.
face is finely reticulate. Occasional pores (c. 1-2fLm diameter) appear to traverse the wall (Fig. 207E,F, arrows).
Suborder BRADORIINA Raymond,1935 Family HIPPONICHARIONIDAE Sylvester Bradley,1961
Material. SAMP30928 from UNEL1846, Cur ramulka, Parara ut. Description. The specimen resembles Gen. et sp. indet. B in outline and marginal rim, but differs in having a reticulate rim and fine denti cles along the posterior margin (Fig. 207H).
Hipponicbarion sp. (Fig. 207A)
lUaterial. SAMP30925 from 6529RS104, Kul para, Parara Lst. preserved in full relief, Description. The has a triangular outline, narrow marginal rim, and slight retral swing. The anterodorsal node connects to a ridge that continues ventrally for about half the width of the valve; a fainter ridge connects with the posterodorsal node. The anterior is distinguished on a slight swing, re garded as retral, and the more pronounced ridge. Comparisons. The specimen resembles B eyri chona longquan.r:iensis Cui & HUD in Cui et aI., 1987 but that species has a more distinct retral swing (Cui et al. ,1987, pU, authorship variously stated as Cui [pp. 77] or Cui & HUD [p.77]; we accept the latter). Family INDIANIDAE Ulrich & Bassler, 1931 Gen. et sp. indet. A (Fig. 207B,C)
Material. SAMP30926 from UNEL1868, Mt. Scott Ra., Ajax ut. Description. Associated valves are preserved in relief, but somewhat offset. The dorsal margin is straight and free margin semicircular. The sur face is smooth and there is no marginal rim. Gen. et sp. indet B
207D-F)
ii.faterial. SAMP30927 from UNEL1846,. Curramulka, Parara Lst. Description. The valve is preserved in relief, but has an inwardly flexed margin. The dorsaJ mar gin is straight and the free margin semicircular, with a distinct rim (Fig. 207D-F). The latter is smooth (Fig. 207F), but otherwise the outer sur-
Gen. et sp. indet C (Fig. 207G,H)
Class, order and family unassigned Isoxys Walcott,1890 *1890 Isoxys Walcott, p.625. ?1981
Glauderia Poulsen; Missarzhevsky & Mam betov, p.59
*1982 Cymbia Jiang in Luo et aI., p.llS.
Remarks. The spine-shaped Glauderia multifi dus, interpreted as a conodont by Mambetoy (in Missarzhevsky & Mambetov,1981), has the same structure as the fossils described herein. Glauderia Poulsen,1967, based on longitudin ally cracked tubes, is better assigned to Cole olaides Wakott,1890 (Brasier,1984, p. 234). Cymbia Jiang in Luo et al., 1982, based on a complete carapace from the Qiongzhusian Stage of Yunnan, is indistinguishable from lsoxys (Conway Morris, 1985; Hou,1987a; HOll & SUD, 1988). Isoxys? sp. A (Fig. 208)
Material. C. 30 specimens from UNEL 1846, Curramulka, Parara Lst. Description. Long and short spines are inter preted as representing the same organism: both have a thick phosphatic wall, median slit and suture, and a broken base that evidently expand ed into a valve-like structure (Fig. 20SA,E,I). Long spines (Fig. 208A-D,G,J-L) reach c. 5mm long and 1mm wide, with a rounded cross section. One side has a prominent V-shaped slit, extending to within c. 200--300lkm of the tip and sometimes continuing further as a crack (Fig. 208C). The opposite side has a faint suture, along which the spine often fractures (Fig. 208H). A transverse section through one of the long spines
Fig. 204. EpactridiOfI portax Bengtson, gen. et sp. nov., carapaces. Curramuika, Parara Lsl., UNEL1846. A-C, SAMP30920. A, right laleral view, x 140, stereo-pair. B, oblique anterior view, x140. C, detail of E, xSOO. D-H, SAMP3092L D, right(?) lateral view, stereo-pair, x90. E, detail of D, x800. F, oblique posterior(?) view, x90. G, oblique ventral view, x90. H, detail of G, x1500.
326
STEFAN BENGTSON et al.
Fig. 205. Epactridion portax Bengtson, gen. et sp. nov., carapace. Curramulka, Parara Lst., UNEL1846. All x90, except B,D, G. Holotype SAMP30922. A, left lateral view, stereo- pair. B, detail of A, x4500. C, oblique ventral view. D, detail of C, x800. E, oblique posterior view. F, oblique anterior view. G, detail of F, x450.
(Fig. 20BK-L) shows the median suture as a structureless crack. The spines are curved ad suturally in the plane of symmetry. Most are broken basally; but rare specimens (Fig. 20BA) show a basal expansion on the side of the V shaped slit. The main part of the spine is smooth,
but towards the base the surface develops a granulation (Fig. 20BA, left). The short spines have the same structure. One well-preserved specimen has its two sides strongly expanding in almost the same plane (Fig. 20BE,F).
Fig. 206. Epactridion portax Bengtson, gen. et sp. nov., carapaces. Curramulka, Parara Lst., UNEL 1846. � .
.
x90. A-C, SAMP30923. A, lateral view, stereo-pair. B, end view. C, ventral view.D-F, SAMP30924.D, later view. E, oblique end view. F, ventral view.
EARL Y CAMBRIAN FOSSILS, S. AUST.
327
328
STEFAN BENGTSON et al.
Fig. 207. Bradoriids. All x50, except where ot herwise stated. A stereo-pair. A, Hipponicharion sp. Kulpara, Parara Lst., 6529RSIlO. SAMP30925 right (?) valve. B,C, Indianidae gen. et sp. indet. A, Mt. Scot! Ra., Ajax Lst., UNEL1868, SAMP30926, carapace, left(?) (B) and dorsal (C) views. D-F, Indianidae gen. et sp. indet . D, Curramulka, Parara Lst., UNEL1846, SAMP30927, right(?) valve, inside. E,F, details, x500. G,H, Indianidae gen. et sp. indet. G, same sample as D-F. SAMP30928, left valve. H, detail of G, x500.
Remarks. The longitudinal slit and suture and rare basal expans ion indicate that the spines derive from a bivalved carapace of Isoxys type, of which co mpletely preserved carapaces occur
in the Lower Cambrian of Australia (Glaessner, 1979a) and China (Hou, 1987a). In the Australian I. communis Glaessner, 1979a, the anterior spine appears to have been the thinner and shorter of
EARLY CAMBRIAN FOSSILS, S. AUST.
329
Fig. 208. Isoxys? sp. A, spines. Curramulka, Parara L st., UNEL1846. All x30, except where otherwise stated. Band E stereo-pairs. A, SAMP30929. B-D, SAMP30930. C, detail ofB, x120. D, x60. E,F, SAMP30931. G,H, SAMP30932. H, x60. r, SAMP30933. J, SAMP30934. K,L, SAMP30935. K, x500, L, detail ofK, x1800.
330
STEPAN BENGTSON et al.
the two, but their development is variable (GIaessner,1979a, p.23). In I. auritus (Jiang in Luo e t al., 1982), the spines are about the same le ngth (Hou,1987a), whereas in I. paradnxus Hou,1987a, the posterior spine i1; considerably longer. Long and short spines in the Parara Lst. are not equally abundant, only one out of six being short. Such a discrepancy may indicate the presence of two species, but it is as likely to be due to variability in spine length comparable to that observed in more fully preserved specimens of lsoxys (GIaessner, 1979a; Hou,1987a). Also, the preservational potential of the longer spines may have been greater - they are generally smoother and may have been more mineralized than the shorter ones. The carapace itself was probably weakly mineralized; fragments are unknown in the Curramulka samples, and more completely preserved specimens are commonly wrinkled (Walcott, 1890, p.626). lsoxys carapaces are usually found closed, but in occasionaf specimens the two valves lie flat on one bedding plane (Hou,1987a, p1.2, figs 3,5). Structure of the Curramulka spines, in particular termination of the ventral slit short of the spine tip, and the simple dorsal suture, suggests that the spines could not freely hinge. Nevertheless, propagation of the open ventral slit into a crack implies that stress was imposed (Fig. 208C). The two valves probably had a limited freedom of movement, due to flexibility of the largely un mineralized cuticle, but rotation around the hinge line decreased toward the spine tips. Open valves of lsoxys (Hou,1987a, p1.2, figs 3,5) were probably buried near their maximum gape and subsequently flattened by compaction.
PROTOCONODONTS [SB] The slender elements of Protohertzina Missar zhevsky,1973 and related forms are referred to as protoconodonts (Bengtson,1976,1977,1983) and are a characteristic component of many of the earliest skeletal faunas. A lamellar structure indicates accretionary growth of the elements on the inner side and basal margin. A striking resemblance between protoconodonts and grasp ing hooks of recent chaetognaths extends to the fine- and ul trastructural levels (Szaniawski, 1982), and suggests an affinity between chaetog oaths and protoconodonts. Protohertzina is one likely candidate for a predatorial role in the ear liest Cambrian ecosystems. Protohertzina also has a special significance in the biostratigraphy of the Precambrian-Cam brian transition. First described from amongst the earliest skeletal faunas in the uppermost Ven-
dian and basal Cambrian ofthe Siberian Platform and Kazakhstan (Missarzhevsky, 1973), Proto hertzina has subsequently been discovered wide ly in China (e.g. Qian,1977; Qian et al., 1979; Jiang,1980a; Luo et al.,1982; Chen, 1982; Qian & Xiao,1984; Qian & Yin,1984a; Li,1984; Yang & He,1984; Qian & Bengtson, 1989), western Canada (Conway Morris & Fritz,1980; Nowlan et al., 1985), the Himalayas (Azmi,1983; Azmi & Pancholi, 1983; Brasier & Singh,1987), and Iran (B. Hamdi pers. comm. 1986). The unguliformis-anabarica group has been regarded as indicative ofthe Precambrian- Cam brian transition, with a type occurrence close to the basal Tommotian along the River Aldan and in the Anabar Massif (Missarzhevsky, 1973, 1982). In other areas they generally occur with the earliest skeletal fossil assemblages. Proto hertzina siciformis has been reported from the Chulaktau Formation of Maly Karatau (Missar zhevsky,1973; Missarzhevsky & Mambetov, 1981), of presumed Tommotian age and strati graphically aboveP. anabarica. Even though" the widespread Protohertzina Anabarites fauna has been taken as an indicator of Precambrian-Cambrian boundary strata, like Anabarites, Protohertzina in the the Atdabanian of Australia extends its range and must cast doubts on the significance of a Protohertzina Anabarites assemblage for global correlation of Precambrian.,....Cambrian boundary strata. Poorly preserved material from Australia may be diffi cult to distinguish from P. anabarica of the Siberian Platform, although the Australian species is probably more closely related to P. siciformis.
Protohertzina Missarzhevsky,1973 *1973 Protohertzina Missarzhevsky, p.54. *1982 Emeidus Chen, p.258. *1984 Hastina Yang & He, p.38.
Type species. Protohertzina anabarica Missar zhevsky,1973. Other species.P. bialata (Yang & He,1984) (=P. unguliformis); P. cultrata Missarzhevsky, 1977; P. interposita Mambetov,1988 (=P. anabarica); P. primitiva (Chen,1982) (?=P. unguliformis); P. quadrigoniata ( Y a n g & H e , 1 9 84) ( =P. anabarica); P. siciformis Missarzhevsky,1973; P. unguliformis Missarzhevsky,1973. Distribution. Siberian Platform, Kazakhstan, Mongolia, China, Australia, India, Iran (B. H a m d i , pers. comm.,1986), northwestern Canada; Lower Cambrian.
EARLY C AMBRIAN FOSSILS, S. AUST.
331
Fig. 209. Protohertzina ef. siciformis Missarzhevsky, 1973. Mt. Seol! R a., Ajax L st., UNEL1873. All x100. A and D stereo-pairs. A-C, SAMP30936. D,E, SAMP30937.
Diagnosis. Slender, spinose, curved, symmet rical, apatitic elements, expanded base and inter nal cavity extending almost to the tip. Walls of fibrous lamellae overlapping obliquely in basal direction on inner side. Elements usually with posterior ridge and a pair of lateral ridges; anterior edge sometimes with weak sulcus and occasionally with anterior ridge.
Protohertzina cf. siciformis Missarzhevsky, 1973 (Fig. 209) Material. SAMP30936, 30937 from UNEL 1873 Mt. Scott Ra., Ajax Lst.
ridges (Fig. 209C,E). The elements are whitish apatite. Taxonomic comparisons. The high median keel characterizes P. siciformis, b u t the lateral 'shoulders' appear to be more pronounced than in the holotype (Missarzhevsky, 1973). The Austral ian specimens resemble P. cf. siciformis of Qian & Bengtson (1989) from the Lower Meishucunian of Yunnan.
Mongolodus Missarzhevsky, 1977 Mongolodus Missarzhevsky, p.17. Ganloudina He; Yang & He, p.39. *1984b Ganloudina He: He in Xing et al., p.178.
19n
Description. Both specimens are slender (1.1 mm long), smooth, and gently curved. The strongest curvature is distal, whereas the proximal part is nearly straight. A prominent posterior keel only becomes subdued at the tip. One specimen (Fig. 209A-C) shows a broadening of the keel near the base. The cross-section is teardrop-shaped, with slight 'shoulders' formed by weak posterolateral
1984
Type species.Mongolodus rostriformis Missar zhevsky,1977. Other species.M.longispina (Yang& He,1984);
332
STEF AN BENGTSON et al.
Fig. 210. Mongolodus cf. rostriformis Missarzhevsky, 1977. Mt. Scot! Ra., Ajax Lst., UNEL1873. All x 100, except G. A,B, SAMP30938. C,D, SAMP30939. E-G, SAMP30940. G, detail of F, xlODO.
M . platybasalis (Yang & He,1984); M. sym metricus (He in Xing et al.,1984b), Distribution. Mongolia, China, Australia; Lower Cambrian. Diagnosis. Phosphatic, thorn-shaped· elements, l aterally flattened, with a posterior basal expan sion. Internal cavity large. Discussion. The possibility that the broad M on golodus elements belong to the same apparatus as the slender ones referred to Protohertzina is worth entertaining. Both have a similar composi tion, and if the length dimension of the Proto hertzina element (Fig. 209A-C) was reduced, the resulting morphology would be similar to Mongolodus (Fig. 210A,B.) However, the pub lished record of geographical and stratigraphical distribution of both forms does not show exact congruence. Mongolodus cf. rostriformis Misarzhevsky, 1977 (Fig. 210)
is round near the tip, becomes laterally flattened basally (Fig. 210B,D,F), while the base itself has a prominent posterior expansion producing a teardrop-shaped cross-section (Fig. 210B). A wide interior cavity is visible basally (Fig. 21OD), but its full apical extent is uncertain. The elements are whitish apatite. Remarks. The described specimens agree well with M issarzhevsky's (1977) account of M. rostriformis. Because only one specimen was figured, the amount of variability in the original type series of six cannot be assessed. The Australian specimens are thus referred to under open nomenclature. The Chinese M . longispina is comparable, but the holotype and only illus trated specimen (Yang & He,1984, pI.2, figs 6,7), although broken, appears to have a more ex panded basal part. Phylum, Class, Order and Family incertae sedis Microdictyon Bengtson et aI., 1981 *
M aterial. Six specimens from UNEL1873, Mt. Scott Ra., Ajax Lst. Description. The thorn-like elements are small (0.40--O.46mm long), with an anterior profile evenly curved through c. 90°. The cross-section
1981
Microdictyon Bengtson et al.; Missarzhevsky & M ambetov, p.78.
1 986
Microdictyon Bengtson et al., p.99.
*1987 Eoconcharium Huo & Shu, p. 304. 1988
Eoconcharium Huo & Shu; Shu & Chen, p.885. [not Eoconcharium Huo &Shu, 1987]
EARLY CAMBRIAN FOSSILS, S. AUST.
Type species. Microdictyon effusum Bengtson et al. in Missarzhevsky & Mambetov, 1981. Other species. M. chinense (Huo & Shu, 1987); M. depressum sp. nov.; M. rhomboidale Beng tson et al.,1986; M. robisoni Bengtson et al., 1986; M. sinicum Chen et al., 1989; M. sphaer oides Hinz, 1987; M.? tenuiporatum Bengtson et al.,1986. Diagnosis. Phosphatic net-like plates with crude ly hexagonal meshwork. Outline varies from rounded oblong through rhombic to more com plex. Plate length ranges from c. O.5-2.5mm. Holes in meshwork round, c. 1O-130J,Lm dia meter, penetrating the plate or terminating with a thin, usually hemispherical bottom. Mush room-shaped or spiky nodes protrude at wall junctions between holes. Holes usually decrease in size toward peripheral girdle. Plates con structed of framework forming the walls and the bottoms (if present) of the holes, and capping making up nodes and crests of the walls. Plates arranged in pairs along body of appendiculate worm-like organism (Chen et al., 1989). Microdictyon depressum Bengtson, sp. nov. (Figs 211, 212) Etymology. Latin depressus, depressed; referring to the flattened plates and nodes. Material. Holotype SAMP30941 (Fig. 211) fmm UNEL1866, Mt. Scott Ra., Ajax Lst.; c. 20 paratypes. Distribution. Horse Gully (6429RSl13), Cur ramulka (UNEL1846-1849, 1763B), Kulpara (6529RS113), Parara Lst.; Mt. Scott Ra., Ajax Lst. (UNEL1866, 1867); Wilkawillina Lst., Wilkawillina Gorge (NMVPL1594). Diagnosis. SubcircuJar plates, flat to slightly convex. Nodes mushroom-shaped, with flat to weakly convex upper surface. Description. In outline plates are subcircular and flat to slightly convex. Observed maximum dimension is 1.8mm; but fragments suggest specimens of several mm diameter. Largest ob served holes are 130J,Lm in diameter (Fig.212H), mesh size decreasing towards the periphery. The nodes are low mushroom-shaped, with flat to slightly convex upper surface, usually with a low tip (Fig.212J). Where the basic hexagonal pat tern is undisturbed, their outline is subcircular. Where this pattern is disrupted, however, the nodes may be larger and sometimes elongate. In such cases the holes may be of unequal diameter
333
(Figs 211, 212A). Holes are open downwards and the cylindrical walls also have weak lon gitudinal Iineations. No closed holes have been observed. The girdle varies in width from c.20 to c.100J,Lm and shows faint radial lineations. Microstructure agrees with that of other Microdictyon species (Bengtson et al., 1986).
SPHERICAL FOSSILS OF UNCERTAIN AFFINITY [SCM] Early Cambrian spherical fossils with either smooth or pustulose surfaces are referred to as Olivooides Qian,1977 (attribution to Jiang by Rozanov [1986] is in error, and is misspelt Olivoides); Tianshandiscus Qian & Xiao,1984; Ambarchaeooides Qian et al.,1979; Aksuglobu Ius Qian & Xiao,1984, Pseudooides Qian,1977; Nephrooides Qian,1977; Protosphaerites Chen, 1982; Mirooides (nomen nudum) Y a n g et al.,1983; Archaeooides Qian,1977; Gaparella Missarzhevsky in Missarzhevsky & Mambetov, 1981, and Meghystrichosphaeridium Chen & Liu,1986. Aetholicopalla adnata gen. et sp. nov., from the Australian sections is described here.
Olivooides Un crushed specimens are strikingly smooth, lacking obvious attachment structures, but usual ly the spheres are crumpled, indicating original flexibility. Beneath this outer coat, a complex array of ?spicules extends outwards in a dense series of pillar-like processes, while at their op posite ends they splay to form an interlocking mass that defines the inner walI (Xing et al.,1984b, p.1 70, p1.28, figs 1,2; Yang et al.,1983, pl.4, figs 6,8; Vue, 1986, pIs 1,2). Qian (1977) erected O. multisulcatus, O. al veus, O. canariculatus, and O. intersulcatus from the Yangtze Gorges, Hubei and Ningqiang, Shaanxi. Jiang (in Luo et al.,1982; see also Luo et aL , 1 984) synonymized the species, but in erecting O. blandes, he violated ICZN regula tions of priority. If the synonymy is accepted, the valid name is O. multisulcatus. A review of the stratigraphic distribution of Olivooides is avail able in Xing et al. ( 1984a; see also He et al.,1984b), on the basis of material from (a) Meishucun sequences in Jinning County, Yun nan (Jiang, 1980a); (b) Ningqiang, Shaanxi (Qian,1977; Xing & Vue in Xing et al.,1984b); (c) various localities in Guizhou (Wang et al. in Xing et al.,1984b; Wang et al.,1984b); (d) Yangtze Gorge, (Qian,1977) including Jijiapo, near Yichang, Hubei (Chen, 1984; identified as
334
STEFAN BENGTSON et al.
Fig. 211. Microdictyon depressum Bengtson, sp. novo Mt. Scott Ra., Ajax Lst., UNEL1866, holotype, SAMP30941 .
?Archaeooides); (e) M a i diping sequences, Sichuan Province (Anon.,1982, pI. 1, fig . 25; specimen identified as Archaeooides), and (f) Nan jiang area, Sichuan (Yang et al.,1983, fig. 6 identified asArchaeooides). However, O. papil� latus from the Gaojiashan Member of the Den gying Formation, Shaanxi (Zhang ,1986) appears to be pyritic spheres (SCM, pers. obs.). Olivooides has been described from the Lower Tal Formation of Uttar Pradesh, India (Bhatt et ai.,1983,1985; Brasier & Singh,1987; Azmi's
(1983, p1.8, fig. 15) reference toArchaeooides cf. granulatus appears inadmissible) and the Hazira Formation in Pakistan (Mostler,1980). Brasier & Singh (1987) regarded features ofOlivooides as consistent with protoctist, a n cysts; perhaps sphaeromorph acritarchs or prasinophyceans. However, Yue (1986) placed this form with the sponges on account of their supposed spicular structure. ' Spherical microfossils Pseudooides prima from Ningqiang, Shaanxi (Qian,1977) and
Fig. 212. Microdictyon depressum Bengtson, sp. 'novo Curramulka, Parara Lst., UNEL1846 (A-H) and UNEL1763B(J,J). All x75 exceptJ. A,B , SAMP30942. C,D, SAMP30943. E,F,SAMP30944. G, SAMP30945. H, SAMP30946.),J,SAMP30947. J, x750, detail, position indicated in J.
EARLY CAMBRIAN FOSSILS, S. AUST.
335
336
STEFAN BENGTSON et al.
Mirooides stetlatus (Yang et al.,1983, specific name also spelt stellalus [p.104]; a nomen nudum lacking diagnosis or holotype designation) may be synonyms of Olivooides. A specimen il lustrated as Tianshandiscus verrucosus from Aksu-Wushi, Xinjiang (Qian & Xiao,1984, p1.2, fig.15) may be comparable to Olivooides. Smooth spheres from the Middle Cambrian Cabitza Formation of southwest Sardinia were referred to agglutinated foraminifers (Cherchi & Schroeder, 1985), and may not be related to Olivooides. Given their problematical status, brief com ments on at least superficially similar structures are appropriate. Crumpled spherical bodies (diameter 0.5 mm) with an organic wall and pyrite filled interior from the Tremadocian of Quebec were described as tasmanitids (Landing et al.,1986) but are similar to Olivooides. Hollow organic spherules from a Cretaceous-Tertiary boundary section in the Italian Apennines (Nas lund et al., 1986), are claimed to be Recent contaminants such as seeds and insect eggs (Montanari,1986).
Aksuglobulus, Ambrachaeooides, Ne phrooides Globular clusters from Aksu-Wushi, Xinjiang described as Aksuglobulus acinosus (Qian & Xiao,1984), and compound spheres from the eastern Yangtze Gorge, Hubei referred to asAm barchaeooides tianzhushanensis (Q i a n et al. ,1979; misspelt Ambachaeooides on p. 232) may be inorganic. Comparable material occurs in a number of Australian samples. Doubt also surrounds the organic nature of Nephrooides speciosus from Emei County (Qian,1977) and the Nanjiang area, Sichuan (Yang et al.,1983).
Meghystrichosphaeridium M. wenganensis and M. chadianensis Chen & Li u, 1986, refer to possible algal spheres, with walls beset with conicaiprotuberances, from late Precambrian Doushantuo phosphorites of Guiz hou and Shaanxi.
Archaeooides
All three species, A. granulatus (type), A. acuspinatus, and A. kuanchuanpuensis (Qian 1977), together with A. interscriptus (Qian, 1978b), may be synonymous. Protosphaerites ningqiangensis, used to describe apparently spherical structures (Chen,1982), is a substitute name for Paramobergella ningqiangensis Zhong [Chen],1977. Erection of the latter name because the etymology of the former was deemed inap propriate is invalid under ICZN regulations. Chen (1982) regarded Protosphaerites [nomen nudum] as a senior synonym of Archaeooides. Although a crushed specimen from Sichuan that Chen (1982, pl.1, fig.10) illustrated as P. granulatus is conceivably comparable to Ar chaeooides, t h e available i l lu s t r a t i o n s o f Paramobergella ningqianensis are too poor to assess a relationship with Archaeooides. Archaeooides is distributed widely in the Chinese Lower Cambrian, and its generally restricted stratigraphic range in each section (He et al . ,1984b; Xing et al., 1984a) might suggest some biostratigraphic utility. Current records in clude 1, Meishucun section, Jinning, Yunnan (Bed 7, Zhongyicun Member; see also Jiang in Luo et al.,1982; 'Gen. et sp. indet' in their p1.23, fig.11 m a y conc eivably be Archaeooides; Jiang,1980a; Luo et al. , 1 984) ; 2, Maidiping sec tion, Emeishan, Sichuan (Beds 36--39, possibly extending fron;t.Beds 31-41, Maidiping Mem
ber; See also He et al.,1984a, but specimen in Anon.,1982, pl.l, fig.25, is questionably referred to Archaeooides) and questionably Nanjiang section (Yang et al., 1983), while Kerber's (1988) suggestion that Uncinaspira squamosa from Leibo, Sichuan (He,1984) is a junior synonym of Archaeooides, is tentative; 3, Shiz honggou section, Ningqiang, Shaanxi (Bed 26) and Yuanjiaping section (Beds 4-5; see also Xing & Yue,1984); 4, Yan'gtze Gorge, Hubei (see also Qian,1978b; Qian et al., 1979); and apparently 5, Aksu-Wushi, Xinjiang, Yurtus Formation, (Qian & Xiao,1984, pl.3, fig.34), al though comparisons with Archaeooides are dif ficult. However, a specimen illustrated as Tianshandiscus verrucosus from the same area (Qian & Xiao,1984, pl.1, fig.8) may represent a flattened Archaeooides. Notwithstanding its potential as an index fossil discrepancies emerge in that its occurrence at Meishucun and Maidip-
Fig. 213. Aetholicopalla adnata Conway Morris, gen. et sp. novo Curramulka, Parara Lst., UNEL1763a (A-I),
UNEL1761 (J), and UNEL1763b (K-P). A-E,holotype, SAMP30948. A, upper view, x50. B, lateral view, x50. C, inner wall and pillars, x300. D,E, wall structure, x180 and x270. F-H. SAMP30949. F, adherent surface, x36. G, surface, x65. H,I, SAMP30950. H, adherent.surface and inner wall, x50. I, surface, x120. J, SAMP30951, upper view, x44. K, SAMP30952, adherent surface, x45. L-N, SAMP30953, polished transverse section. L, x55. M, adherent surface, x550. N, upper surface, x215. O-P, SAMP30954, attached to hyolith tube; 0, x55. P, lateral view, x90.
EARLY CAMBRIAN FOSSILS, S. AUST.
337
338
STEFAN BENGTSON et al.
ing are in the Paragloborilus - Siphogonuchites . spicules, trilobite pleurae, hyoliths and other assemblage, whereas those of Ningqiang are tubes. within the underlying Anabarites - Circotheca Protohertzina assemblage. Comparisons. This genus superficially resem Archaeooides has been recorded from Salany blesArchaeooides, but features corresponding to gol, Mongolia (Voronin et al.,1982), in the the detailed wall structure and encrusting habit Tienchoshan Formation (IlsanelLa compressa of Aetholicopalla adnata seem to be absent. Zone), correlated with the Tommotian of the Specimens f rom t h e Lower Cambrian o f southern France that Kerber (1988, pU1, figs Siberian Platform (L. tortuosa Subzone of the D. regularis Zone). On the Lena River sections 13-20) referred to Archaeooides granulatus are (Siberian Platform) Archaeooides is known from reassigned to Aetholicopalla, possibly con the BergeronielLus micmacciformis - Erbiella specific withA. adnata. Unequivocal encrusting Zone (= P. squamosus - B. zelenovi Zone), habit (Kerber, 1988, pUl, figs 13, 18) and lower Botomian (Sokolov & Zhuravleva,1983), reticulation of the inner wall (Kerber, 1988, but in northern Siberia it occurs in ostensibly pUl, fig.19a,b) support this proposal. p r e-Tommo t i a n s t r a t a ( V al'k o v , 1 9 8 7 ) . Aetholicopalla adnata Conway Morris, sp. Goryansky (1973) regarded irregular spherical fossils from the Lenian (=Botomian) sections on novo (Figs 213-216) the River Kotui, northeast Siberia, as possibly 1988 Archaeooides granulatus Qian; Kerber, p.189, Chancelloria; Qian's (1977) comparison with p1.11, figs 13-20. Archaeooides seems questionable. Reports of Archaeooides from the Lower Cambrian of Etymology. Latin adnatus, adherent; on account Herault, southern France (Kerber,1988) are more likely to be Aetholicopalla gen. novo Gaparella of its encrusting habit. porosa Missarzhevsky (in Missarzhevsky & Mambetov,1981) may be synonymous withAr Material. Holotype SAMP 30948 (Fig. 213A-E) chaeooides and occurs in the Shabakty Forma from UNEL1763a, Curramulka, Parara Lst.; 34 tion (Maly Karatau, Kazakhstan), a unit within figured paratypes and C. 100 other specimens. t h e Rhombocorniculum cancellatum Z o n e Distribution. Curramulka, Parara Lst. (UNEL (Adyshevitheca Subzone), regarded as upper At dabanian. A specimen from the Tal Formation of 1763a,b, 1848, 1849, 1851, NMVPL95); Horse India identified as Maikhanella sp. (Bhatt et Gully, farara Lst. (UNEL1854, 1856); Mt Scott Ra., Ajax Lst. (UNEL1871, 1872, 1877, ?1874). al. ,1985) may be Archaeooides. If stratigraphic correlations in Mongolia, Kazakhstan and Diagnosis. As for the genus. Siberia are reliable, Archaeooides has an exten sive range in the Lower Cambrian. Description. Preservation is phosphatic, but etched surfaces of the outer wall reveal no ultrastructure (Fig. 213L-N), suggesting that the phosphate is diagenetic. Evidence for moulding Kingdom, phylum, order, family uncertain and accommodation to substrates suggests also Aetholicopalla Conway Morris, gen. novo that in life the sphere was pliable and perhaps lightly mineralized. The interior also is filled Etymology. Greek aitholix, pimple, and palla, with phosphate, but apart from the tubules it is ball; referring to its shape. Gender is feminine. interpreted as secondary. The approximately spherical specimens (Figs 213A,B,J, 214A,N, 215A,B,D,G-:-L, 2161, J,L), Type and only species. Aetholicopalla adnata Conway Morris, sp. novo usually have a flattened area (Figs 213F, H,K, 214C) corresponding to a zone of attachment. A Diagnosis. Spherical; ?originally calcareous. prolific sample (67 specimens) from UNEL1849 Bounding surface composed of closely spaced reveals a unimodal distribution (Fig. 217), with double walls, inner defining central cavity oc a mean diameter of C. 0.57mm. Degree of ec cupied by vermiform tubules. Walls connected centricity is restricted, with a mean ratio (n=65) of 1: 1.06, and a maximum ratio not exceeding by hollow pillars, containing tubular structures that open on outer surface via perforations. Outer 1:1.37. surface otherwise subdued botryoidal. Exterior An encrusting cryptic habit is evident from surface of inner wall with reticulate ornamenta attachment (herein; Kerber,1988) to substrates tion between connecting pillars. Encrusting such as the inner .surfaces of hyolithids and other habit, attachment surfaces include chancelloriid tubes (Figs 2130,P, 215N,O), the basal opening
EARLY CAMB RIAN FOSSILS, S. AUST.
339
Fig. 214. Aetholicopalla adnata Conway Morris, gen. et sp. novo Curramulka, Parara Lsl., UNEL1763b (A-F), UNEL1848 (G-H), UNEL1851 (I). Horse GuI\y, Parara Lsl., UNEL1854 (J), UNEL1856 (K-M). MI. Scott Ra., Ajax Lsl., UNEL1872 (N). A,B, SAMP30955. A, x65. B, outer surface with embedded sponge spicule, x240. C-F, SAMP30956. C, x65. D, adherent surface and inner wall, x275. E, inner wall, x300. F, pillars and canals, x650. G,H, SAMP30957. G, upper view, x40. H, lateral view, x48. I, SAMP30958, interior, x75. J, SAMP30959, x80. K-M, SAMP30960. K, x65. L, possible attachment surface, x65. M, detail of L, x215. N, . SAMP30962, x65.
of isolated chancelloriid spicules (Fig. 215M), trilobite pleura (Fig. 215Q,R), and unidentifiable
shell fragme nts ( F i gs 213A,B, 2 14G,H, 216E,G). The broad, flat surface on one side of
340
STEFAN BENGTSON et al.
most specimens represents an attachment zone, to a substrate that either detached or failed to be phosphatized. This zone usually is either flat or gently curved, but sometimes sharply angled or recurved (Fig. 213K) indicating accommodation to a more restricted space (Fig. 216G). Aetholicopalla consists of a double wall, separated by short pillars without a regular arran gement, enclosing an interior cavity (Figs 213D,E,G,I, 2140, 2150, 2161,K). The outer wall normally is absent, so the projecting array of pillars (Figs 213C, 214E) gives the fossil a spinose appearance (Figs 2131, 215A,G-L,O, 216L). The lower preservation potential of the outer wall may reflect postmortem wear, original mineralogy, and/or preferential phosphatization of the inner wall. The connecting pillars are hoUow and may house a central thin-walled canal (Fig. 214F). The pillars opened into the interior of the sphere, and if they perforated the outer wall they could have provided direct access from the interior to the outside medium. Exterior perforations occur on the attachment surface (Fig. 213F,H,K), but here they could not have been functional. Elsewhere on the outer surface perforations are usually not evident (Figs 213A,0,E,O,P, 214A,N, 2150, 216G,H), unless dimples that overlie the connecting pillars repre. sent openings occluded' by a secondary phos phatic crust. Presumably, such a coating could not gain access to the surface formerly welded to the adjacent substrate, and so here the perfora tions remain open. The exterior surface of the outer wall is sub dued botryoidal to nodose (Figs 213A,E,P, 216H), and apart from putative canal openings is relatively featureless. In contrast, the exterior surface of the inner wall has a closely spaced reticulation of narrow ridges that define a crude ly polygonal pattern (Figs 213C,I, 214F, 216K), but it resembles neither epithelial imprints· (Okada,1981,1982; Curry & Williams, 1983; Tanabe & Fukuda,1983), nor epitaxial replicas' of shell microstructure (Runnegar & Bentley, 1983; Runnegar,1985b). Conceivably a now vanished layer (?calcium carbonate) was sand wiched between the two walls, with the reticulation reflecting an impression of the inner side. The inner surface of the in tenor wall lining
the central cavity is most evident where a section of wall adheres to a substrate (Figs 215P, 216A E). This surface is relatively featureless apart from the densel y spaced openings to the connect ing canals. The interior of the sphere may be more or less hollow, but more often is filled with presumably diagenetic phosphate. Mingled with this infill ing, however, are vermiform tubules that may be primary (Fig. 215B,C), which in polished and etched sections (Fig. 215E,F) reveal a phosphatic coating that may represent either diagenetic re placement of a ?calcareous wall or epitaxial overgrowth of an organic wall. Their irregular arrangement indicates that they formed a loosely coiled mass. It is not clear how the tubules were inter-connected, nor is there evidence of direct continuity with the connecting canals leading towards the exterior. Other vermiform structures attached to the interior wall show a radiating arrangement (Fig. 216A,B,0). They may have been linked to the internal tubules, but they bear no direct relationship to adjacent pores marking the openings to the connecting canals. Comparisons; Archaeooides, with its papillate surface, might invite comparison with individ uals of Aetholicopalla lacking their outer wall. However, examination of the surface of the former (Qian & Bengtson,1989) failed to demonstrate pillar structures or an intervening reticulate ornamentation as inAetholicopaUa (cf. Kerber,1988). Rather, in Archaeooides the sur face papilli seem simpler (Missarzhevsky & Mambetov,1981, p1.13, fig. 1), although the diagenesis of these spheres has not been studied. Moreover, Archaeooides appears to lack a flat tened surface of attachment, unless this feature occurs in a specimen of Archaeooides sp. from near Yichang, Yangtze Gorge, Hubei (Qian et ai.,1979, pIA, fig.18). Biology. If the phosphatic walls arose by secon dary diagenesis, they may represent epitaxiai overgrowths of ?ca1careous wall or direct re placement of original double walls. The internal tubules are regarded as primary, but possibly unmineralize,d. If this is correct, then originally Aetholicopalla was a perforated sphere occupied
Fig. 2]5. Aetholicopalla adnala Con way Morris, gen. et sp. nov. Curramulka, Parara Lst., UNEL1763a (A-D), UNEL1763b (E,F), UNEL1849 (G-O), UNEL1850 (P-R). A-C, SAMP30963. A, oblique view, x70. B, lateral view, x70. C, inner wall and tubules, x260. D, SAMP30964, oblique view, x78. E,F, SAMP30965, polished section. E, longitudinal section of tubule, x1135. F, transverse section of tubule, x545. G, SAMP30966, x60. H, SAMP30967, x120. I, SAMP30968, x45.1, SAMP30969, x50. K, SAMP30970, x60. L, SAMP3097I, x50. M, SAMP30972, specimen in chancelloriid spicule, x40. N,O, SAMP30973, specimen in hyolith tube. N, x40. 0, oblique view, x80. P, SAMP30974, interior, x70. Q,R, SAMP30975, specimen in trilobite pleuron. Q, xI8. R, upper view, xI8.
EARLY CAMBRIAN FOSSILS, S. AUST.
341
342
STEFAN BENGTSON et al.
Fig. 216. Aetholicopalla adnata Conway Morris, gen. et sp. novo Curramulka, Parara Lst., UNEL1849 (A-E). Mt. Scott Ra., Ajax Lst., UNEL1871 (F-I), UNEL1877 (J-L). A-C, SAMP30976. A, interior, x60. B, detail, x 130. C, internal openings, x545. D, SAMP30977, interior, x75. E, SAMP30978, interior, x70. F, SAMP30979, flattened specimen, x35. G,H, SAMP30980, specimen attached to tube. G,x70. H, surface, x260. I, SAMP30981, x 105. J,K, SAMP30982. J, oblique view, x95. K, x175. L, SAMP30983, oblique view, x75.
by tubules, the latter having access to the exterior via the pores but probably without direct connec tions. Aetholicopalla is not comparable to a free living metazoan, and similarities to groups such as sponges, including the Cambrian Blastlllos pongia (Pickett & Jell, 1983; Bengtson,1986; White,1986; ConwayMorris & Chen,1989a) are superficial. The encrusting and cryptic habit of Aetholicopalla indicates that it may be a resting
body or a stage in a life cycle, for storage of propagules to be released via the pores for dis persal. However, even if this interpretation is accepted, its affinities remain unresolved. The internal tubules recall algal filaments, and their diameter (c. 30J.Lm) hints at a eukaryotic affinity. S i l i ceous c h r y s o p hycean r e s t i n g b o d ies (Sandgren,1983) only super ficially resemble Aetholicopalla. A number of microfossils also show similarities to Aetholicopalla. The Or-
EARLY CAMBRIAN FOSSILS, S. AUST.
n ·67 i ·O·S7mm SO· 0·11
Fig. 217. Size frequency histogram of 67 specimens of Aetholicopalla adnata Conway Morris, g�n. et sp. novo from Curramulka, Parara Lst., UNEL1849.
dovician and Silurian mazuelloids (Aldridge & Armstrong,1981; Burrett, 1985; Holmer,1987) may have a double wall, separated by pillars, enclosing a spherical interior. However, they differ in being smaller, phosphatic, lacking an attachment surface, and bearing prominent ex ternal spines. Comparisons might be drawn also with Meghystrichosphaeridium from the late Precambrian of Guizhou and Shaanxi (Chen & Liu,19 8 6), which is comparable in size to Aetholicopalla. However, the ornamentation of conical protuberances does not resemble the
343
inter-wall pillars of Aetholicopalla. A more remote resemblance also exists with the Or dovician phosphatic problematicum described by Eisenack (1971, fig.53a,b) as Object C (Zahnbogen or 'tooth-arch'). Broad simil arities exist with such groups as the ca1cipheres (Stan ton,1967), parathuramminacean fusuline foram iniferids (Loeblich & Tappan,1964), and the Lower Proterozoic microproblematicum Val lenia (Bondesen et al.,1967).
Acknowledgements We are grateful to Mr Alan G. Pavey and family of Ardrossan for hospitality and for access to the section at Horse Gully. Publication of this Memoir was made possible through a grant from the University of New England. SB thanks Meit Lindell for extensive picking of etched residues, Tommy Westberg, Martin Feuer, Meit Lindell, Goran Blom, Lars Holmer, and Christer Back for darkroom work, Dagmar Engstrom and Christina Franzen-Bengtson for assistance with the preparation of figures, and N.P. Meshkova and Qian Yi for the gift of specimens of key taxa illustrated herein (Figs 22
Fig. 218. Reconstruction of Aetholicopalla adnala Conway Morris, gen. et sp. nov., with section cut away to reveal interior tubules. Specimen attached to shell fragment
344
STEFAN BENGTSON et al.
and 133). SB's participation in the project was made possible by the award of a University of New England Visiting Research Fellowship and subsequent grants from the Swedish Natural Science Research Council and the UppsaJa University. Part of the work on the manuscript was carried out the tenure of a Senior Research Fellowship at the University of CaliLos 1"""'1",<0,'''". Sandra Last for Skinner for and Sheila Ken Harvey and Christina photographic printing, Zoe Conway for picking of fossiliferous residues and help with from Nuffield Founplate dation for Newly appointed Science Swedish Natural Sciences Research Council, and the Cowper-Reed Fund is gratefully acknowledged. PJ thanks Directors bf the Museum 6fVictoria and the Queensland Museum for the use of facilities to carry out the project, Penny Clark, Lyn Anderson, MyJes Wilmott, Enid Mark Burrows, Frank Annette Jell, Jane Alexander Peter Corcoran, David Gravestock, Christopher
and Neale Hall for assistance with one or more aspects of collecting, preparation, photography, curation, or typing, Or L.N. Repina, Novosibirsk, Or Richard Fortey, Lolland Prof. A.R. Palmer, Boulder for loan of <:"f'(" rnf'fl<: or provision of moulds that were used and Prof. AR. Palmer and Prof. in this W.T. Chang, Nanjing for useful discussion and comment. David Gravestock, South Australian of Mines kindly refereed this memoir and made available the lithological sec tion (Fig.8) from work in preparation. BR is grateful to ChriStopher Bentley, F.A. (Angus) Shaw, Bryan Stait, and Kathi Stait for and Oh'DtO'IH,Ihelp with collecting, phy.Many excellent were nr"'n<>rpri by Nick Pctrasz and John Cook were photographed with the assistance of Shirley Dawson. SEM work was carried· out with the of Christopher Bentley and Peter most of the photographic prints were prepared Barbara Ward. BR's research was the Australian Research Grants financed Scheme (Project E7915353) and the University of New England.
EARLY CAMBRIAN FOSSILS, S. AUST.
345
REFERENCES ABAIMOVA,G.P.,1976. Samye drevnie gastropody Sibiri. (The oldest Siberian gastropod). Trudy Inst. Geol. Geo/iz. sib. Otd. 296,174-175. (Russian). ABAIMOVA, G.P., 1978. Anabaritidy drevneyshie iskopaemye s karbonatnym skeletom. (Anabaritids the oldest fossils with a calcareous skeleton). Trudy
sib. nauchno.-issled. Inst. Geol. Geofiz. miner. Syr'. 260,77-83. (Russian). ALDRIDGE, RI. & ARMSTRONG, H.A., 1981. Spherical phosphatic microfossils from the Silurian of north Greenland. Nature 292,531-533. ALDRIDGE, R.l., SMITH, M.P., NORBY, RD. & BRIGGS, D.E.G.,1987. The architecture and func tion of Carboniferous polygnathacean conodont ap paratuses. In Palaeobiology of Conodonts, RI. Aldridge,ed.,EIlis Horwood,Chichester,63-75. ALLER,R.C.,1974. Prefabrication of shell ornamen tation in the bivalve Laternula. Lethaia 7,43-56. ALVAREZ, F., CURRY, G.B. & BRIME,c., 1985. Contribucion al estudio comparativo de la estruc tura y crecimiento de la concha de braquiopodos actuales y fosiles. Trabajos de Geologia 15, 211217. ANONYMOUS,1979. Younger Precambrian strata in Suxiang and Emei regions in west Sichuan. In Col lections of Essays on International Geologic Cor relation - Strat., Pal. 2. Geological Publishing Co., 55-64. [Authorship given as Younger Precambrian Group,Chengdu Geological Institute] (Chinese). ANONYMOUS, 1982. Brief introduction to the Sinian-Cambrian Boundary section of Mount Emei, Sichuan Province, China. Sinian �esearch Group, Chengdu College of Geology, ChIna, 44p. (Chinese and English). AZMI,R.l., 1983. Microfauna and age of the Lower Tal phosphorite of Mussoorie Sync1ine, Garhwal Lesser Himalaya, India. Himalayan Geology 11, 373-409. AZMI, R.l. & PANCHOLI, V.P., 1983. Early Cambrian (Tommotian) conodonts and other shelly microfauna from the upper Krol of the Mussoorie Sync1ine, Garhwal Lesser Himalaya with remarks on t h e P r e c a m b r i a n - C a m b r i an B o u ndar y . Himalayan Geology 11,360-372. BAYER, F.M., 1956. OctocoraIlia. In Treatise on invertebrate paleontology, Part F, Coelenterata, RC. Moore, ed., Geological Society of America, B o u l d e r , a n d U n i v e r s i t y of Kansas Press, Lawrence,F166-F231. B E L Y A E V A , G . V . , L UC HI N I N A, V . A . , NAZAROV, B.B., REPINA, L.N. & SOBOLEV, L.P., 1975. Kembriiskaya fauna i flora khrebta Dzhagdy (dal'nii vostok). (Cambrian fauna and flora of the Dzhagdy Ranges - Far East). Trudy Inst. Geol. Geo/iz. Sib. Otd. 226, 121-124. (Russian). BENGTSON, S., 1968. The problematic genus Mobergella from the Lower Cambrian of the Baltic area. Lethaia 1, 325-351. BENGTSON, S., 1970. The Lower Cambrian fossil Tommotia. Lethaia 3,363-392. BENGTSON,S.,1976. The structure of some Middle Cambrian conodonts, and the early evolution of
conodont structure and function. Lethaia 9, 185206. BENGTSON,S., 1977a. Aspects of problematic fos sils in the early Palaeozoic. Acta Universitatis Up saliensis, Abstracts of Uppsala Dissertations from the Faculty of Science, 415,71p. BENGTSON, S., 1977b. Early Cambrian button shaped phosphatic microfossils from the Siberian Platform. Palaeontology 20,751-762. BENGTSON, S., 1981. Atractosella, a Silurian al cyonacean octocoral. J. Paleont. 55, 281-294. BENGTSON,S., 1983. The early history of the Con odonta. Fossils and Strata 15, 5-19. BENGTSON, S., 1985a. Taxonomy of disarticulated fossils.J. Paleont. 59,1350-1358. BENGTSON, S., 1985b. Redescription of the Lower Cambrian Halkieria obliqua Poulsen. Geol. Foren. Stockh. Forh. 107,101-106. BENGTSON,S.,1986a. A new Mongolian species of the Lower Cambrian genus Camenella and the problems of sc1eritome-based taxonomy of the Tommotiidae. Paldont. Z. 60,45-55. BENGTSON,S.,1986b. Siliceous microfossils from the Upper Cambrian of Queensland. Alcheringa 10, 195-216. BENGTSON,S. & CONWAY MORRIS,S.,1984. A comparative study of Lower Cambrian Halkieria and Middle Cambrian Wiwaxia. Lethaia 17, 307329. BENGTSON, S. & FLETCHER, T.P., 1983. The oldest sequence of skeletal fossils in the Lower Cambrian of southeastern Newfoundland. Can. J. Earth Sci. 20,525-536. BENGTSON, S., MATTHEWS, S.c. & MIS SARZHEVSKY, V.V., 1986. The Cambrian net like fossil Microdictyon. In Problematic fossil taxa, A. Hoffman & M.H. Nitecki,eds, Oxford Univer sity Press,New York,197-115. BENGTSON,S. & MISSARZHEVSKY,V.V.,1981. Coelosc1eritophora - a major group of enig matic Cambrian metazoans. U.S. geol. Surv. Open-File Rept 81-743 , 19-21. BENTOR, Y.K., 1980. Phosphorites - the unsolved problems. Spec. Publ. Soc. Econ. Paleont. Miner. 29,3-18. BERG-MADSEN, V., 1981. The Middle Cambrian Kalby and Borreglird Members of Bornholm,Den mark. Geol. Foren. Stockh. Forh. 103,215-231. BERG-MADSEN, V., 1985. A r e v i e w of the Andrarum Limestone and the upper alum shale (Middle Cambrian) of Bornholm, Denmark. Bull. geol. Soc. Denm. 34,133-143. BERG-MADSEN, V. & PEEL, I.S., 1978. Middle Cambrian monoplacophorans from Bornholm and Australia, and the systematic position of the bel lerophontiform molluscs. Lethaia 11,113-125. BERG-MADSEN, V. & PEEL, I.S., 1987. Yochel cionella (Mollusca) from the late Middle Cambrian of Bornholm, Denmark. Bull. geol. Soc. Denm. 36, 259-261. BHATT, D.K., MAMGAIN, V.D. & MISRA, RS., 1985. Small shelly fossils of early Cambrian (Tom-
346
STEFAN BENGTSON et al.
motian) age from Chert-Phosphorite Member,Tal Formation, Mussoorie Syncline, Lesser Himalaya, India and their chronostratigraphic evaluation. 1. palaeont. Soc. India 30, 92-102. BHATT, D.K., MAMGAIN, V.D., MISRA, R.S. & SRIVASTAVA, I.P., 1983. SheIIy microfossiIs of Tommotian age (Lower Cambrian) from the Chert Phosphorite Member of Lower Tal Formation,Mal deota, Dehra Dun district, Uttar Pradesh. Geo phytology 13, 11 6-123. BILLINGS, E., 1871. On some new species of Palaeozoic fossils. Canadian Naturalist 6, 213223,240. BILLINGS, E., 1872. On some fossils from the primordial rocks of Newfoundland. CanadianNat. 6,465-479. BINKS, P., 1968. Orroroo Map Sheet, Geological Atlas of South Australia, '1 :250,000 series. Geol, Surv. Sth. Aust., Adelaide. BISCHOFF, G.C.O., 1976. Dailyatia,a new genus of the Tommotiidae from Cambrian strata of SE Australia (Crustacea, Cirripedia). Senckenb. leth. 57,1-33. BISCHOFF,G.CO., 1978. Internal structures of con ulariid tests and their functional significance,with special reference to Circonulariina n. suborder. Senckenberg. letk 59, 275-327. BISCHOFF,CG.O., 1989. Byroniida new order from early Palaeozoic strata of eastern Australia (Cnid aria,thecate scyphopolyps). Senckenberg. leth. 89, 467-521. BOCKELIE, T.G., BRUTON, D.L. & FORTEY, R.A., 1977. Research on the Ordovician rocks of North Ny Friesland, Spitsbergen. Arbok, norsk Polarinst. (/977),214-215. BOCKELIE, T. & FORTEY, R.A., 1976. An early Ordovician vertebrate.Nature 260,36-38. BOKOVA, A.R., 1985. Drevneyshiy kompleks or ganizmov kembriya zapadnogo Prianabar'ya (An cient organisma from the Cambrian of the western Prianabar region). Stratigrafiya rozdnego dokem briya i rannego paleozoya Sibirii Vend i Rifey, 13-27. (Russian). BONDESEN, E . , PEDERSEN, K . R . & J0RGENSEN, 0., 1967. Precambrian organisms and the isotopic composition of organic remains in the Ketilidian of south-west Greenland. Meddr Gr"nland 164, 141. BRASIER,M.D., 1976. Early Cambrian intergrowths of a r c h a e o c y a t h i d s , Renalcis a n d p s e u d o stromatolites from South Australia. Palaeontology 19,223- 245. BRASIER, M.D., 1979: The Cambrian radiation event. Syst.Ass. Spec. Vol. 12,103-159. (Academic Press,London). BRASIER, M.D., 1984. Microfossils and small shelly fossils from the Lower Cambrian Hyolithes Lime stone at Nuneaton, English Midlands. Geol. Mag. 121,229-253. BRASIER, M.D., 1986a. Precambrian-Cambrian boundary biotas and events. In Global bio-events. Lecture notes in Earth Sciences 8, 0. Walliser,ed., Springer-Verlag,Berlin,109-117. BRASIER, M.D., 1986b. The succession of small shelly fossils (especially conoidal microfossils)
from English Precambrian-Cambrian boundary beds. Geol. Mag.123, 237-256. BRASIER,M.D., 1989. Towards a biostratigraphy of the earliest skeletal biotas. In The Precambrian Cambrian boundary,J.W. Cowie & M. D. Brasier, eds,Clarendon,Oxford,117-165. BRASIER, M.D. & SINGH, P., 1987. Microfossils and Precambrian-Cambrian boundary stratigraphy at Maldeota, Lesser Himalaya. Geol. Mag. 124, 323- 345. BULYGO, L.V., IVSHIN, N.K. & KONEVA, S.P., 1 9 8 1 . 0 vydelenij mobergellovykh sloev v Seletinskom sinklinorii (tsentral'nyj Kazakhstan). (On the recognition of the Mobergella beds in the Seletin Synclinorium (central Kazakhstan». /zv. Akad. Nauk. kazakh. SSR, ser. geol. 1 981(5), 4850. (Russian). BURNETI, W.C., 1977. Geochemistry and origin of phosphorite deposits from off Peru and Chile. Bull. geol. Soc. Am. 88,813-823. BURRETI,C, 1985. Problematic,phosphatic micro spheres (mazuelloids) from the Ordovician of Tas mania,Australia. Alcheringa 9,158. CARLISLE,D.B., 1964. Chitin in a Cambrian fossil, Hyolithellus. Biochem. 1 .90, lc-2c. CHAPMAN, F., 1918. Ostracoda from the Upper Cambrian limestone of South Australia. Proc. R. Soc. Vict. n.s. 31, 108-112. CHEN JUNYUAN, HUO XIANGUANG & LU HAOZHI, 1989. Early Cambrian netted scale-bear ing worm-like sea animal. Acta palaeont. sin. 28, 1-16. (Chinese. English summary). CHEN MENGE,1979a. Some skeletal fossils from the phosphatic sequence,early Lower Cambrian, south China. Scient. geol. sin. 4, 187-189. (Chinese, English summary). CHEN MENGE, 1979b. (On the fossil Zhijinites from the phosphorus-bearing sequence, early Lower Cambrian, South China). Scient. geol. sin. 1979, 279- 281. (Chinese,English summary). CHEN MENGE, 1982. (The new knowledge of the fossil assemblages from Maidiping section, Emei County, Sichuan with reference to the Sinian Cambrian boundary). Scient. geol. sin. 1982,253262. (Chinese,English summary). CHEN MENGE & LIU KUIWU, 1986. (The geologi cal significance of newly discovered microfossils from the Upper Sinian (Doushantuo age) phos phorites. Scient. geol. sin. 1986,40-53.(Chinese, English summary). CHEN PING, 1984. (Discovery of Lower Cambrian small shelly fossils from Jijiapo, Yichang, West Hubei and its significance). Prof Pap. strat. palaeont., 13,49-64. (Chinese,English summary). CHEN, R.Y., 1985. Lower Cambrian trilobites from Liangshan District of Nanzheng, Shaanxi. Acta palaeont. sin. 24, 332-336. CHEN YIYUAN & W ANG ZIQIANG, 1985. A bivalve of the Lower Cambrian Xinji Formation in western Henan Province. Earth Science 1. Wuhan Coli. Geol. 1 0 , 27-29.(Chinese). CHEN YIYUAN & ZHANG SHU-SHEN, 1980. Small shelly fossils from the early Lower Cambrian, Songlinpo, eastern Yangtse Gorges. Geol. Rev. 26, 190-197. (Chinese).
EARLY CAMBRIAN FOSSILS, S. AUST.
CHEN YIYUAN, ZHANG SHUSEN,LIU GUIZHI, XIONG XINGWU,CHEN PING et ai, 1984. (The Sinian-Cambrian boundary in the eastern part of the Yangtze Gorges, Hubei). Bull. Inst. Geol., Chinese Acad. geol. Scis 10,14-35. (Chinese). CHERCHI, A. & SCHROEDER, R., 1985. Middle Cambrian Foraminifera and other microfossils from SW Sardinia. Boil. Soc. paleont. ital. 23,149-160. CHERNYSHEV A, N .E., 1950. Novye sredne kembriyskie trilobity Vostochnoy Sibiri (New Mid dle Cambrian trilobi.tes from eastern Siberia). Trudy nauchno.-issled. Geol.lnst. (VSEGEI) 1,67-77. CHUVASHOV, B. & RIDING, R., 1984. Principal floras of Palaeozoic marine calcareous algae. Palaeontology 27,487-500. CLARKE, I.D.A.,1986a. Subdivision of the lower part of the Wilkawillina Limestone, eastern Flinders Ranges. Q. geol. Notes, geol. Surv. S. Aust. 97,12- 16. CLARKE,I.D.A.,1986b. Stratigraphic subdivision of the Early Cambrian Parara Limestone at WilkawiI Iina Gorge, Flinders Ranges. Q. geol. Notes, geol. Surv. S. Aust. 99,2-7. CLARKE, I.D.A.,1986c. Stratigraphy and sedimen tology of the upper part of the Wilkawillina Lime stone, Wilkawillina Gorge, Flinders Ranges. Q. geol. Notes, geol. Surv. S. Aust. 100,2-7. COATS,R.P., 1973. Copley Map Sheet, GeoLogical Atlas of South Australia 1:250,000 series. Geol. Surv. Sth. Aus!.,Adelaide. COBBOLD, E.S., 1921. The Cambrian horizons of Comley (Shropshire) and their Brachiopoda, Pteropoda,Gasteropoda,etc. Q. Jl geol. Soc. Lond. 76,325-386. COB BOLD, E.S., 1934. The Cambrian genus Stenotheca. Geol. Mag. 71,463...:..468. COBBOLD,E.S.,1935. Lower Cambrian faunas from Herault, France. Ann. Mag. nat. Hist., ser. 10, 16, 25-48. COBBOLD, E.S. & POCOCK, R.W., 1934. The Cambrian area of Rushton,Shropshire. Phil. Trans. R. Soc. B 223,305-409. CONWAY MORRIS,S.,1985. The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia,Canada. PhiL Trans. R. Soc. B 307,507586. CONWAY MORRIS, S., 1987. The search for the Precambrian-Cambrian boundary. Am. Scient. 75, 156- 167. CONWAY MORRIS, S.,1988. Radiometric dating of tbe Precambrian-Cambrian Boundary in the Avalon Zone. Bull. N. Y. St. Mus. 463,53-58. CONWAY MORRIS, S. & CHEN MENGE, 1989. Lower Cambrian anabaritids from south China. GeoL Mag. 126;615-632. CONWAY MORRIS, S. & CHEN MENGE,1990a. Blastulospongia polytreta n. sp., an enigmatic or ganism from tbe Lower Cambrian of Hubei,China. J. PaLeont. 64,26-30. CONWAY MORRIS, S. & CHEN MENGE, 1990b. Tomotiids from tbe Lower Cambrian of south Cbina.J. Paleont. 64,169-184. CONWAY MORRIS,S. & CHEN MENGE,in press. Cambroclaves and paracarinacbitids,early skeletal
347
problematica from the Lower Cambrian of south China. Palaeontology. CONWAY MORRIS,S. & FRITZ,W.H.,1980. Shel Iy microfossils near the Precambrian-Cambrian boundary, Mackenzie Mountains, northwestern Canada. Nature 286,381-384. CONWAY MORRIS,S. & FRITZ,W.H.,1984. Lap worthella filigrana n.sp. (incertae sedis) from the Lower Cambrian of the Cassiar Mountains, north ern British Columbia, Canada, with comments on possible levels of competition in the early Cambrian. Palaom. Z. 58,197-209. CONWAY MORRIS, S. & IENKINS, R.J.F., 1985. Healed injuries in Early Cambrian trilobites from South Australia. Alcheringa 9,167-177. CONWAY MORRIS, S. & ROBISON, R.A., 1988. More soft-bodied animals and algae from the Mid dle Cambrian of Utah and British Columbia. Paleont. Contr. Univ. Kansas Pap. 122,1-48. COOK,P.I. & SHERGOLD,J.H.,1984. Phosphorus, p h o s p horites a n d skeletal evo lution at tbe Precambrian-Cambrian boundary. Nature 308, 231-236. COOK, P.I. & SHERGOLD, 1.H., 1986. Phosphate deposits of the world. Volume 1. Proterozoic and Cambrian phosphorites. Cambridge University Press,386p. COOPER,R.A. & GRINDLEY,G.W.,eds,1982. Late Proterozoic to Devonian sequences in southeastern Australia, Antarctica and New Zealand and their correlation. Spec. PubL geoL Soc. Aust. 9,1-103. C O S S M A N N , M . , 1902. Rectifications de la nomenclature. Revue crit. Paleozool. 6(1),16. COWEN,R.,1968. A new type of delthyrial cover in the Devonian brachiopod Mucrospirifer. Palaeon tology 11,317-327. COWIE, I.W.,1971. Lower Cambrian faunal provin ces. In Faunal provinces in space and time, F.A Middlemiss,P.F. Rawson,G. Newall,eds,Geol.J. Spec. Issue 4,31-46. CRAWFORD, AR., 1960. Maitland Map Sheet, Geological Atlas of South Australia, 1 :253,440 series. Geol. Surv. Sth. Aus!.,Adelaide. CRIMES,T.P.,1987. Trace fossils and correlation of late Precambrian and Early Cambrian strata. Geol.Mag. 124,97-119. C U I ZHILIN, ZHANG XIGUANG, TONG HAOWEN & HUO SHICHENG,1987. (Ontogeny of some Cambrian bradoriids from China). J. NW Univ., Xian 17, 66-77. (Chinese, Englisb sum mary). CURRY, G.B. & WILLIAMS, A, 1983. Epithelial moulds on tbe sbells of tbe early Palaeozoic brachiopod Lingulella. Lethaia 16,111-118. DAILY, 8.,1956. The Cambrian in soutb Australia. XX Int. geol. Congr., Mexico 2,91-147. DAILY,B.,1969. Fossiliferous Cambrian sediments and low grade metamorpbics, Fleurieu Peninsula, Soutb Australia. In Geological Excursions Hand book, B. Daily, ed.,Aus!. N.Z. Ass. Adv. Sci.,41st Congr.,Sect. C,Adelaide,49-54. DAILY, B.,1972. The base of tbe Cambrian and the first Cambrian faunas. In Stratigraphic problems of the later Precambl'ian and Early Cambl'ian, J.B. Jones & B. McGowran, eds, The University of
348
STEFAN BENGTSON et al.
Adelaide Centre for Precambrian Research, Spe cial Paper I, 13-4l. DAILY, B., 1976. Novye dannye ob osnovanii kembriya v Yuzhnoj Australii. (New data on the basal Cambrian of southern Australia). Izv. Akad. Nauk. SSSR, ser. geol. 1976 (3),45-52. (Russian). DAILY, B., FIRMAN, J.B., FORBES, B.G. & LINDSAY, J.M., 1976. Geology. In Natural his tory of the Adelaide region, e.R. Twidale, M.J. Tyler & B.P. Webb, eds, R. Soc. Sth. Aus!., Adelaide 5-42. DAILY, B.D.,MILNES, A.R.,TWIDALE, e.R. & BOURNE, 1.A., 1979. Geology and geomorphol ogy. In Natural History of Kangaroo Island,Tyler, M.I., Twidale, e.R. & Ling, J.K., eds, R. Soc. Sth Aust., Adelaide, 1-38. DAILY,B.,IAGO,J.B. & lAMES, P.R., 1982. Lower Cambrian sediments, Precam brian-Cambrian boundary and Delamerian tectonics of southern Fleurieu Peninsula. In Fourth International Sym posium on Antarctic Earth Sciences, excursion guide B3, geology of the Adelaide region, R.L. Oliver & e.G. Gatehouse, eds, Adelaide, 30-41. DAILY, B., FORBES, B.G. & COATS, R.P., 1982. Archaean, Proterozoic and lower Palaeozoic geol ogy, Eyre Peninsula and Flinders Ranges. In Fourth International Symposium on Antarctic Earth Scien ces, excursion guide A , R.L. Oliver & e.G. Gatehouse, eds, Adelaide, 37-72. DALGARNO, e.R., 1964. Lower Cambrian stratig raphy of the Flinders Ranges. Trans. R. Soc. S. Aust. BB, 129-144. DALGARNO, e.R. & JOHNSON, J.E., 1964. Blin man Map Sheet, Geological Atlas of South Australia, 1 mile series. Geol. Surv. Sth. Aus!., Adelaide: DALGARNO, C.R. & JOHNSON, J.E., 1965. Oraparinna Map Sheet, Geological Atlas of South Australia, 1 :63,360 series. Geol. Surv. Sth. Aus!., Adelaide. DALGARNO, C.R. & JOHNSON, J.E., 1966. Parachilna Map Sheet, Geological Alias of Soulh Australia, 1 :250,000 series. GeoL Surv. Sth Aus!., Adelaide_ DANIELLI,H.M.C., 1981. The fossil alga Girvanella Nicholson & Etheridge. Bull. Br. Mus. nal. Hist. (Geol). 35, 79-107. D A T S E N KO, V . A . , Z H U R A V L EVA LT. , LAZARENKO, N.P., POPOV, Yu.N. & CHER NYSHEVA, N.E., 1968. Biostratigrafiya i fauna kembriyskikh otlozheniy severo-zapada Sibirskoy platformy. (Biostratigraphy and fauna of Cambrian deposits of the northwest Siberian Platform). Trudy nauchno-issled. Inst. Geol. Arkt. 155, 213p. (Rus sian). DEBR ENNE, F., 196 9 . Lower Cambrian Ar chaeocyatha from the Ajax Mine, Beitana, South Australia. Bull. Br. Mus. nat. Hist. (Geol.) 1 7(7), 295-376. DEBRENNE, F., 1970. A revision of Australian genera of Archaeocyatha. Trans. R. Soc. S. Aust. 94, 21-49. DEBRENNE, F., 1974a. Les archeocyathes irreguliers d' Ajax Mine (Cambrien inferieur; Australie du Sud). Bull. Mus. natn. Hist. nal. Paris 195, Sc;'
Terre 33, 185-258. DEBRENNE, F., 1974b. Anatomie et.systematique des archeocyathes reguliers sans plancher d' Ajax Mine (Cambrien inferieur, Australie du Sud). Geobios 7, 91-138. DEBRENNE, F. & GRAVESTOCK, DJ., 1990. Ar chaeocyatha from the SeHick Hill Formation and Fork Tree Limestone on Fleurieu Peninsula,South Australia. Spec. Publ, geol. Soc. Aust. 16, 290-309. D E BRE N N E, F . &. R O Z A N O V , A., 1 9 8 3 . Paleogeographic and stratigraphic distribution of regular Archaeocyatha (Lower Cambrian fossils). Geobios 16, 727- 736. DONOVAN, S. & PAUL, e.R.e., 1985. A new pos sible armoured worm from the Tremadoc of Shein ton) Shropshire. Proc. Geol. Ass. 96, 87-91. DORE,F. & REID,R.E., 1965.Allonnia tripodophora novo gen., novo sp., nouveHe eponge du Cambrien inferieur de Carteret (Manche). Cr. somm. seanc. Soc. geol. Fr. 1965, 20-2l. DUAN CHENGHUA, 1984. (Small shelly fossils from the Lower Cambrian Xihaoping Formation in the Shennongjia District, Hubei Province - hyoliths and fossil skeletons of unknown affinities). Bull. Tianjin Inst. Geol. Miner. Res. 7, 143-188. (Chinese, English summary). DZIK,J., 1986. Turrilepadida and other Machaeridia. In Problematic fossil taxa, A. Hoffman & M.H. Nitecki, eds, Oxford University Press, New York, 116-134. EDHORN, A., 1979. Girvanella in the 'button algae' h o r i z o n of t h e F o r t e a u Formation (Lower Cambrian), western Newfoundland. Bull. Cent. Rech. Explor.-Prod. Elf-Aquitaine 3,557-567. EGOROVA, L.1. & S AVITSKY, V.E., 1969. Stratigrafiya i biofatsii kembriya sibirskoi platfor my (Zapadnoe Prianabar'e). (Cambrian stratig raphy and biofac.ies of the Siberian Platform (western Prianabar)). Trudy sib. nauchno-issled. Inst. Geol. GeoJiz. miner. Syr'. 43, 83-405. EISENACK, A., 1971. Die Mikrofauna der 08t seekalke (Ordovizium). 3. Graptolithen, Melano skleriten, Spongien, Radiolarien, Problematica nebst 2 Nachtragen. iiber Foraminiferen und ·Phytoplankton� Neues Jb. Geol. Paliiont. Abt. 137, ·337-357. ERWIN,D.H. & VALENTINE,l.W., 1984. 'Hopeful monsters', transposons, and metazoan radiation. Proc. naln. Acad. Sci. U. S. A. Bl, 5482-5483. ETHERIDGE, R., 1898. Pt further Cambrian trilobite .
from Yorke Peninsula. Trans. R. Soc. S. Aust. 22, 1- 3. ETHERIDGE, R., 1905. Additions to the Cambrian fauna of South Australia. Trans. R. Soc. S. Aust. 29,246-25l. ETHERIDGE, R., 1919. The Cambrian trilobites of Australia and Tasmania. Trans. R. Soc. S. Aust. 43, 373-393. . FEDONKIN, M.A., 1983. Organicheskij mir venda. (Organic world of the Vendian). Itogi Nauki i Tekhniki VINITlAN SSSR, ser. slrat. paleont. 12, 1-127. (Russian). FEDONKIN, M.A., 1986. Precambrian problematic animals: their body plan and phylogeny. In Problematic fossil taxa, A. Hoffman & M.H.
EARLY CAMBRIAN FOSSILS, S. AUST.
Nitecki, eds, Oxford University Press, New York, 59-67. FEDOROV,A.B.,1984. Novye predstaviteli skeletnoj org aniki v stratotipicheskikh razrezakh dokembriya-kembriya Sibirskoj platformy (reki Aldan,Kotuj). (New representatives of skeletal or g a n i s m s f r o m t h e P rec am b ri a n- C a m b r i a n stratotype sections of the Siberian platform (rivers Aldan and Kotui». In Novye vidy drevnikh bespozvonochnych i rastenij nejtegaznosny tsij Sibiri, SNIGGIMS,Novosibirsk,5-9. ). F E D O R O V , A . B . , 1 9 8 6 . N o v ye t r u b c h a t y e problematiki i z stratotipa Tommotskogo yarusa. (New problematical tubes from the type Tom motian section). Paleont. Zh. 1986(2) 110-111. (Russian). FINKS,R.M.,1970. The evolution and ecologic his tory of sponges during Palaeozoic times. Sym. zool. Soc. Lond. 25,3-22. FINKS, R.M., 1983. Fossil Hexactinellida. Univ. Tenn. Dept. Geol. Scis, Studs Geol. 7,101-115. FISHER,D.W.,1962. Small conoidal shells of uncer tain affinities. In Treatise on invertebrate paleon tology, Part W, Miscellanea, R.C. Moore, ed., W98-WI43. FLEMING, P.I.G., 1973. Bradoriids from the Xyst ridura Zone of the Georgina Basin, Queensland. Publ. geol. Surv. Qd 356,1-9. FLETCHER, A.W., 1890. Ordinary meeting luly 1 1890. Exhibits. Trans. R. Soc. S. Aus. 13,249. FONIN, V.D. & SMIRNOVA, T.N., 1967. Novaya gruppa problematicheskikh rannekembryskikh or ganizmov i nekotoryye metody iz preparirovaniya. (A new group of problematic Early Cambrian or ganisms and some methods of preparing them). Paleont. Zh. 1967(2),15-27. (Russian). FOSTER, C.B., CERNOVSKlS, A. & O'BRIEN, G.W.,1985. Organic-walled microfossils from the Early Cambrian of South Australia. Alcheringa 9, 259- 268. FRETTER, V. & GRAH A M , A., 1 9 7 8 . T h e prosobranch molluscs o f Britain a n d Denmark. Part 4 - marine Rissoacea. J. Moll. Stud., Suppi. 6, 153-236. FRITZ,W.H., 1972. Lower Cambrian trilobites from the Sekwi Formation type section, Mackenzie Mountains,northwestern Canada. Bull. geol. Surv. Can. 212, 1-58. FRITZ, W.H., 1973. Medial Lower Cambrian trilo bites from the Mackenzie Mountains northwestern Canada. Pap. geol. Surv. Can. 13-24,1-43. GAO ZHENJIA, WU SHAOZU, LI YONGAN & QIAN JIANXIN,1982. Research on stratigraphy of the Sinian-Cambrian sequences in Aksu-Kalpin region,Xinjiang. Kexue Tongbao 27,524-527. GATRALL, M. & GOLUBIC,S.,1970. Comparative study on some lurassic and Recent endolithic fungi using scanning electron microscopy. Geol. J. Spec. Issue 3,167-178. GAZDZICKI, A. & WRONA, R., 1986. Polskie badania paleontologiczne w Antarktyce Zachodniej (1986). (Polish paleontological investigations in West Antarctica (1986». PrezgladGeologiczny 11, 609- 617. (Polish,English summary). GEYER, G., 1986. Mittelkambrische Mollusken aus
349
Marokko und Spanien. Senckberg. leth. 67, 55118. GEYER, G., 1988. Agnostida aus dem hOheren Un terkambrium u n d dem Mittelkambrium von Morokko. Teil 2: Eodiscina. Neues Jb. Geol Pallion!. Abh. 177,93-133. GLAESSNER,M.F.,1976. Early Phanerozoic annelid worms and their geological and biological sig nificance. Q. JI geol. Soc. Lond. 132, 259-275. GLAESSNER, M.F., 1979a. Lower Cambrian Crus tacea and annelid worms from Kangaroo Island, South Australia. Alcheringa 3, 21-31. GLAESSNER,M.F.,1979b. Precambrian. In Treatise on invertebrate paleontology, Part A, Fossilization (Taphonomy), Biogeography and Biostratigraphy, R.A. Robison & C. Teichert, eds, Geological Society of America & University of Kansas Press, Boulder and Lawrence,A79-A118. GOLUBIC, S., PERKINS, R.D. & LUKAS, K.I., 1975. Boring microorganisms and microborings in carbonate substrates. In The study of trace fossils, R.W. Frey,ed.,Springer-Verlag,Berlin, 229-259. GORYANSKY, V.Yu., 1973. 0 neobkhodimosti isklucheniya roda Chancelloria Walcott iz tipa gubok. (On the necessity of exclusion of Chancel loria Walcott from the Phylum Porifera). Trudy Inst. Geol. Geofiz. sib. Otd. 49,34-44. (Russian). GORYANSKY, V.Yu. & POPOV, L.Ye., 1986. On the origin and systematic position of the calcareous shelled inarticulate brachiopods. Lethaia 19, 233240. GRABAU, A.W., 1900. Palaeontology of the Cambrian terranes of the Boston Basin. Oec. Pap. Boston Soc. fUlt. Hist. 4, 601-694. GRAVESTOCK,DJ.,1983. Structure and function of the exothecal tissue of Somphocyathus coralloides Taylor and allied regular Archaeocyatha. Mem. Ass. Australas. Palaeontols. 1,67-74. GRAVESTOCK, DJ., 1984. Archaeocyatha from lower parts of the Lower Cambrian carbonate se quence in South Australia. Mem. Ass. Australas. Palaeontols 2, 1-139. GREEN, I.W., KNOLL, A.H. & SWETT, K., 1988. Microfossils from oolites and pisolites of the Upper Proterozoic Eleonore Bat Group, central East Greenland. J. Paleont. 62, 835-852. G R I G O R'E V A , N . V. , 1 9 8 0 . K v o p r o s u ob issledovanii mikrostruktury khiolitel'mintov. (To the question of microstructural investigations of hyolithelminths). In Paleontologiya. Stratigrafiya - MezhdunorodnyjGeologicheskij Kongress, XXVI Sessia, Doklady Sovetskikh Geologov, 49-55. (Russian). GRIGOR'EVA, N.V., MELNIKOVA, L.M., PEL'MAN Vu. L., 1983. Brakiopody, ostrakody (bradoriidy) i problematika iz stratotipicheskogo rayona yarusov nizhnego kembriya. (Brachiopods, ostracodes (bradoriids) and problematica from the stratotypic region of the Lower Cambrian stages). Paleont. Zh. 1983(3),54-58. (Russian). GRIGOR'EVA, N.V. & ZHEGALLO,E.A.,1979. K issledovanii mikrostruktur nekotorykh tommot skikh iskopaemykh. (To the study of the micro structure of some Tommotian fossils). Paleont. Zh. 1979(2),142-144. (Russian).
350
STEFAN BENGTSON etal.
HALL,J. & CLARKE, J.M., 1899. A memoir on the Paleozoic reticulate sponges constituting the Fami� Iy Dictyospongidae.Mem. N.Y. St. Mus. 2, 1- 197. HAO YICHUN & SHU DEGAN, 1987. The oldest known, well-preserved Pheodaria (Radiolaria) from southern Shaanxi. Geoscience 1987(1), 301310. (Chinese,English summary). HE TlNGGUl, 1981. (Sachitida from Meishucun Stage of Lower Cambrian and their stratigraphical significance).]. Chengdu CoIL Geol. 1981(2),8490. (Chinese). HE TlNGGUl, 1984. (Discovery of Lapworthella bella assemblage from Lower Cambrian Meishu CUD Stage in Niuniuzhui, Leibo County, Sichuan Province). Prof. Pap. Strat. Paleont. 13, 23-34. (Chinese,English summary). HE TINGGUl, 1987. (Early Cambrian conulariids from Yangtze Platform and their early evolution). l. Chengdu Coli. Geol. 14, 7-18. (Chinese,English summary). HE TlNGGUl, DlNG LlANFANG et al., 1984a. (The Sinian-Cambrian boundary in southwestern part of Sichuan). Bull. Inst. Geol. Chinese Acad. Geol. Scis 10,64-90. (Chinese). HE TINGGUl, DlNG QIXIU, LUO HUlLlN & XING YUSHENG, 1984b. (Biotic characteristics of the Sinian-Cambrian Boundary beds in China). Bull. Inst. Geol., ChineseAcad, Geol. Scis 10,1 26138. (Chinese). HE TINGGUl & PEI FANG, 1985. (The discovery of bivalves from the Lower Cambrian Xinji Formation in Fangchang County, Henan Province). J. Chengdu Coli. Geol. 1985(1), 61-66.(Chinese). HE TlNGGUl, PEI FANG & FU GUANGHONG, 1984. (Some small shelly fossils from the Lower Cambrian Xinji Formation in Fangcheng County, Henan Province). Acta palaeont. sin. 23, 350357.(Chinese, English summary). HE TINGGUl & Y ANG XIANHE, 1982. (Lower Cambrian Meishucun Stage of the western Yangtze stratigraphic region and its small shelIy fossils). Bull. Chengdu lnst. Geol. miner. Res. 1982,69-95. (Chinese,English summary). HENNINGSMOEN, G., 1957. The trilobite Family Olenidae with description of Norwegian material and remarks on the Olenid andTremadocianSeries. Skr. Norsk. Vidensk.�Akad. Oslo, math.N nat. Kl. 1957(1), 1-303. HENNINGSMOEN, G., 1958. Los Trilobites de las capas de Saukianda,Cambrico inferior, en Andal� ucia. Estudios geol. Inst. Invest. geol. Lucas Mal� lada 14, 251-271. HEWIlT, R.A., 1980. Microstructural contrasts beN tween some sedimentary francolites. J I geol. Soc. Lond. 137,661-667. HICKS, H., 1872. On some undescribed fossils from the Mendevian Group. Q. Jl geol. Soc. Lond. 28, 1 73-185. HINZ,1.,1987. The Lower Cambrian microfauna of Comley and Rushton, Shropshire, England. Palaeontographica A 198,41-100. HOLM, G., 1893. Sveriges kambrisk�siluriska Hyo� lithid�och Conulariidre. Sver. geol. Undersok., ser. C l12,1-172.(Swedish,English summary). HOLMER, L.E., 1987. Ordovician mazuelloids and
other m i crofossils from Vastergotland. Geol. Foren. Stockh. Forh. 109,67-71. HORNY, R.J.,1964. The Middle Cambrian Pelagiel lacea of Bohemia (Mollusca). Sb. nur. Mus. Praze 20B,133-140. HOU XIANGUANG, 1987a. (Early Cambrian large bivalved arthropods from Chengjiang,eastern Yun� nan). Acta palaeont. sin. 26, 286-298. (Chinese, English summary). HOU XIANGUANG, 1987b. Oldest Cambrian bradoriids from eastern Yunnan. I n Stratigraphy andpalaeontology o/systemic boundaries in China - Precambrian-Cambrian Boundary 1. Nanjing Univ. Publ. House, Nanjing, 537-545. HOU XIANGUANG & SUN WEIGUO, 1988. (Dis covery of Chengjiang fauna at Meishucun,Jinning, Yunnan). Acta palaeont. sin. 27, ]-12. (Chinese, English summary). HOWCHIN, W., 1897. On the occurrence of Lower Cambrian fossils in the Mount Lofty Ranges. Trans. R. Soc. S. Aust. 21, 74-86. HOWELL,B.F. & VAN HOUTEN,F .B.,1940. A new sponge from the Cambrian ofWyoming. Bull. Wag� nerFreelnst. Sci.Philad.15, 1-8. HUO SHIHCHENG, 1956. (Brief notes on Lower CambrianArchaeostracafrom Shensi and Yunnan), Acta palaeont. sin. 4, 425�446. (Chinese). HUD SHIHCHENG, 1965. (Additional notes on Lower Cambrian Archaeostraca from Shensi and Yunnan). Acta palaeont. sin. 13, 291-307. (Chin� ese, English summary). HUO SHIHCHENG & SHU DEGAN, 1982. (Notes on Lower Cambrian Bradoriida (Crustacea) from western Sichuan and southern Shaanxi. Acta palaeont. sin. 21,322-329. (Chinese,English sum� mary).
H U O SHIHCHENG & SHU DEGA N , 1 9 8 5 . (CambrianBradoriida o/South China)., Northwest Univ. Press, Xian. (Chinese, English summary). HUPf, P., 1953. Contribution a l'etude du Cambrien inferieur et du Precambrien III de PAnti�Atlas marocain. Notes Mern. Serv. Mines Carte geoL Maroc. 103,1-402. (French). HURST, J.M. & HEWITT, R.A., 1977. Tubular Problematica from the type Caradoc (Ordovicial;l) of Eng land. Neues lb. Geol.' Palaont. Abh. 153, 147-169. JAANUSSON,V., 1971. Evolution of the brachiopod hinge. Smithson.'contr. Paleobiol. 3, 33-46, JAGO,J.B & DAILY, B.D., 1982. South Australia. Spec. Publ. geol. Soc. Aust. 9,6-12. JAGO,J.B., DAILY,B.D.,VON DER BORCH,C.C., CERNOVSKIS,A. & SA UNDERS,N.,1984. First reported trilobites from the Lower Cambrian Nor� manville Group, Fleurieu Peninsula, South Australia. Trans. R. Soc. S Aust. l08, 207-211. JAGO, J.B., GEHLlNG, J.G. & DAILY, B., 1986. Cambrian sediments of the Sellick Hill - Carrick� alinga Head area, Fleurieu Peninsula, South Australia. In O n e day geological excursion o/the Adelaide region, A.J. Parker,ed., Geol. Soc. Aust., S. Aust. Division, Adelaide, 67-81, JAGO,J.B. & YOUNGS,B.C.,1980. Early Cambrian trilobites from the Officer Basin, South Australia. Trans. R. Soc. S. Aust. 104, 197-199. ..
,
EARLY CAMBRIAN FOSSILS, S. AUST.
JAMES,N.P. & KLAPPA,C.F., 1983. Petrogenesis of Early Cambrian reef limestones, Labrador, Canada.J. sed. Pet. 53,1051-1096. JELL, P.A., 1974. Faunal provinces and possible planetary reconstruction of the Middle Cambrian. J. geol. 82,319-350. JELL,P .A.,1975. Australian,Middle Cambrian eodis coids with a review of the superfamily. Palaeon tographicaA 150, 1-97. JELL, P A., 1978. Trilobite respiration and genal caeca. Alcheringa 2,251-260. JELL,P.A.,1980. Earliest known pelecypod on Earth a new Early Cambrian genus from South Australia.Alcheringa 4,233-239. JELL, P.A., 1981. Thambetolepis delicata gen. et sp. nov.,an enigmatic fossil from the Early Cambrian of South Australia.Alcheringa 5,85-93. JELL, P.A., 1984. A larger bivalve arthropod from SADME Edeowie-l well of probable Cambrian age. Trans. R. Soc. S. Aust. 107,123-125. JENKINS,R.J.F.,1985. The enigmaticEdiacaran (late Precambrian) genus Rangea and related forms. Paleobiology 11,336--355. JENKINS,R.J .F.,1990. The Adelaide Fold Belt: tec tonic reappraisal. Spec. Publ. geol. Soc. Aust. 16, 396--420. JEPPSSON, L., 1979. Conodont element function. Lethaia 12,153-171. JIANG ZHIWEN,1980a. (fhe Meishucun Stage and fauna of the Jinning County, Yunnan). Bull. ChineseAcad. Geol. Scis ser.l, 2,75-92. (Chinese, English summary). JIANG ZHIWEN, 1980b. (Monoplacophorans and gastropods fauna of the Meishucun Stage from Meishucun section,Yunnan). Acta geol. sin. 1980, 112-123. (Chinese,English summary). JIANG ZHIWEN, 1984a. (Evolution of early shelly metazoans and basic characteristics of the Meishu cun fauna). Pro/. Pap. Strat. Palaeont. 13, 1-22. (Chinese,English summary). HANG ZHIWEN, 1984b. Global distribution of the earliest shelly metazoans. Geol. Mag. 121, 185188. JIANG ZHIWEN & HUANG ZHAOBI,1986. Mid dle Cambrian small shelly fauna in Yaxian County, Hainan Island. Geol. Rev. 32,317-324. (Chinese, English summary). JONES,P.J. & McKENZIE,K.G.,1980. Queensland Middle Cambrian Bradoriida (Crustacea): new taxa,palaeobiogeography and biological affinities. Alcheringa 4,203-225. JONES,W.c.,1970. The composition,development, form and orientation of calcareous sponge spicules. Symp. zool. Soc. Lond. 25,91-123. KERB ER, M., 1988. Mikrofossilien aus unterkam brischen Gesteinen der Montagne Noire, Frank reich. PalaeontographicaA 202,127-203. KHALFIN, L.L. ( ed.), 1960. B io stratigrafiya paleozoya sayano-altayskoy gomoy oblasti. (Biostratigraphy of the Palaeozoic of the Sayan Altay mountains region). Trudy nauchno-issled. Inst. Geol. Geofiz. Miner. Syr'. 19,1-498. KHOMENTOVSKY, V.V. & REPINA, L.N., 1965. Nizhniy kembriy stratotipicheskovo razreza Sibiri. (The Lower Cambrian of the stratotype section of
351
Siberia). Sib. otd. Inst. geol. Acad. Sci. USSR, Moscow. (Russian). KLING, S.A. & REIF, W.-E., 1969. The Paleozoic history of amphidisc and hemidisc sponges: new evidence from the Carboniferous of Uruguay. J . Paleont.43, 1429-1434. KOBA YASHI, T., 1933. Upper Cambrian of the Wuhutsui Basin, Liaoning, with special reference to the limit of the Chaumitien (or Upper Cambrian) of eastern Asia, and its subdivision. Jap. J. Geol. Geog�11,55-155. KOBAYASHI,T.,1935. Cambro-Ordovician forma tions and faunas of South Chosen,palaeontology 3. J. Fac. Sci.Imp. Univ. Tokyo, Sec.2, 4(2),49-344. KOBA YASHI, T., 1942. Two Cambrian trilobites from the Parara Limestone in the Yorke Peninsula, South Australia. Proc. imp. Acad. Japan 18, 492498. KOBAYASHI, T., 1944a. On the eodiscids. J. Fac. Sci.Imp. Univ. Tokyo, sec.2, 7(1), 1-74. KOBAYASHI, T.,1944b. The Cambrian formations in the middle Yangtse Valley and some trilobites contained therein. Miscellaneous notes on the Cambro-Ordovician geology and palaeontology no. 15. Jap. J. Geol. Geogr. 19,1-4. KOROBOV,M.N.,1963. Novye trilobity iz nizhnego kembriya Kharaulakhskikh gor. (New trilobites from the Lower Cambrian of Charaulach Moun tain). Paleont. Zh. 1963(4). (Russian). KOROBOV, M.N., 1980. Biostratigrafiya i miomer nye trilobity nizhnego Kembriya Mongolii. (Biostratigraphy and miomeric trilobites of the Lower Cambrian of Mongolia). Trans. Joint Sov. Mong. Sci. Res. Geol. Exp. 26,5-108. (Russian). KRUSE, P.D., 1987. Further Australian Cambrian sphinctozoans. Geol. Mag. 124, 543-553. LAFARGUE, F. & LAUBIER, L., 1980. Lignee evolutive chez led Didemnidae des cOtes de France. Valeur systematique des spicules. Annls Inst. oceanogr., Monaco 56,21-44. LANDING,E., 1984. Skeleton of lapworthellids and the suprageneric classification of tommotiids (Early and Middle Cambrian phosphatic problematica).J. Paleont. 58,1380-1398. LANDING, K, 1988. Lower Cambrian of eastern Massachusetts: Stratigraphy and small shelly fos sils.J. Paleont. 62,661-695. LANDING, E., 1989. Paleoecology and distribution of the Early Cambrian rostroconch Watsonella crosbyi Grabau.J. Paleont. 63,566--573. LANDING, E., BARNES, c.R. & STEVENS, R.K., 1986. Tempo of earliest Ordovician graptolite faunal succession: conodont-based correlations from the Tremadocian of Quebec. Can.J. Earth Sci. 23,1928-1949. LANDING, E. & BRETT, C.E ., 1982. Lower Cambrian of eastern Massachusetts: microfaunal sequence and the oldest known borings. Abscts Prog. geol. Soc. Am. 14,33. LANDING,E.,NOWLAN,G.S. & FLETCHER,T.P., 1 98 0 . A microfauna associated with Early Cambrian trilobites of the Callavia Zone,northern Antigonish Highlands,Nova Scotia. Can. J. Earth Sci. 17,400-418. LAURIE, J.R., 1986. Phosphatic fauna of the early
352
STEFAN BENGTSON et ai,
Cambrian Todd River Dolomite, Amadeus Basin, central Australia. Alcheringa 10,431-454. LAURIE,J.,1987. The musculature and vascular sys tems of two species of Cambrian Paterinide (Brachiopoda), BMR JI Aust, 'Geol,Geophys, 10, 261-265, LAURIE, I, & SHERGOLD, I,H., 1985, Phosphatic organisms and the correlation of Early Cambrian carbonate formations in central Australia. BMRJl Aust, Geol, Geophys, 9, 83-89, LAZARENKO, N,P" 196 4 , Komplesky nizhnekembriyskikh trilobitov severnoi chasti Srednei Sibiri. (Complexes of Lower Cambrian trilobites of the northern part of Middle Siberia). Trudy nauchno-issled.lnst. Geol.Arkt.137, 166287, (Russian), LENDZION,K"1972a, The stratigraphy of the Lower Cambrian in the Podlasie area. Biul. Inst. geol. Warsawa 233,69-157. LENDZION, K " 1972b, Sub·Holmia Cambrian deposits i n the north-eastemareaof Poland. Kwart. geol, 16, 557-568, LERMONTOVA, E,V" 1940, Arthropoda, In Atlas rukovodyashchikh form iskopaemykh faun SSSR, vol. 1, Jiembriy. (Atlas of the leading forms of the fossil fauna o f the USSR, vol, I, Cambrian), AG, Vologdin,ed" VSEGEl, Moscow,193p, (Russian), LERMONTOVA, E,V" 1951. Ni,hnekembriyskie trilobity i brakhiopody Vostochnoy Sibiri. (Lower Cambrian trilobites and brachiopodsfrom eastern Siberia). Gosgeolizdat, Moskva, 222p. (Russian). LIBROVICH, L.S., 1929. Uralonema karpinskii novo gen., nov. sp. i drugie kremnevye gubki iz kamenM nougol'nykh otlozhenij vostochnogo sklona Urala. (Uralonema karpinskii nov gen., novo sp., and other siliceous sponges from Carboniferous deposits of the eastern Ural slope). Trudy geol. Kom., n.s., 179, 11-57,(Russian), LI ZHONGPING, 1984, (The discovery and its sig· nificance of small shelly fossils in the Hexi area, Xixiang, Shaanxi). Geology of Shaanxi 2, 73-77. (Chinese, English summary). LI YUWEN, 1975. (Cambrian ostracodes and their new knowledge from Sichuuan, Yunnan, and Shaanxi.) I n Stratigraphy, palaeontology, Ed. Comm., Acad. Geol. Sci., ed., Geology Press, BeijM ing, 37-72, (Chinese, English summary), LI YUWEN, 1981. (Additional material of bradoriids from the Lower Cambrian Chiungchussu FormaM tion in Emei, Sichuan). Acta palaeont. sin. 20, 71-74. (Chinese, English summary). LlN JlNLU, FULLER, M, & ZHANG WENYOU, 1985. Paleogeography of the North and South China blocks during the Cambrian.J. Geodynam. 2, 91-114, LlN TlANRUl, 1979, On some Middle Cambrian bradoriids from Yaxian, Hainan Island, Guandong. Acta palaeont. sin. 18,574 -578. (Chinese, English summary). LlN TlANRUl, 1987, (Early Cambrian bradoriids from Yeshan, Luhe District, Jiangsu). Acta palaeont. sin. 26, 84-85. (Chinese, English sumM mary), LlNAN, E, & GONZALO, R" 1986, Trilobites del Cambrico inferior y medio de Murero (Cordillera
Iberica). Mem. Museo Paleont. Univ. Zaragoza 2, 1-10 4, LlNAN, E, & SDZUY, K., 1978, A trilobite from the Lower Cambrian of Cordoba (Spain) and its stratigraphical significance. Senckenberg. leth. 59, 387-399, LlNDSTROM, M" 1978, An octocoral from the Lower Ordovician of Sweden. Geologica et Pal� aeontologica 12, 41-52. LlU DlYONG,1979, (Ear liest Cambrian brachiopods from southwest China).Actapalaeont.sin.18,505511. (Chinese, English summary). LOCH MAN, C, 1956, Stratigraphy, paleontology, and paleogeography of the Elliptocephala asaph� oides strata in Cambridge and Hoosick Quadran gles, New York, Bull, geol, Soc, Am, 67, 133113 96, LOEBLlCH, AR, & T APPAN, H" 1964, Protista 2, Sarcodina, chiefly 'Thecamoebians' and Foram-inM iferid a. In Treatise on invertebrate paleontolog YI PartC,R.e. Moore,ed., Geological Society of Am erica and University of Kansas Press, Lawrence, Kansas, C l-C900, LOWENSTAM, HA & MARGULlS, L., 1980, Evolutionary prerequisites for early Phanerozoic calcareous skeletons. BioSystems 12, 27-41. LU YANHOU,1940, 0 n the ontogeny and phylogeny of Redlichia intermedia Lu (sp. nov.). Bull. geol. Soc, China 20, N34, LU YANHOU, 1950. New species of Redlichia. Geological Review 15(4-6). Geological Publishing House, Beijing. LU YANHOU,1961. New Lower Cambrian trilobites from etistern Yunnan. Acta palaeont. sin. 9, 299328, LU YANHOU, 1981. Provincialism, dispersal, development, and phylogeny of trilobites. Spec. Publ, geol, Soc, Am. 187,143-151. LU YANHOU (inter alia), 1957, Trilobita, I n Index fossils of China, part 3, Inst. Palaeont. Academia Sinica, Geological Publishing House, Beijing, 249294, LU YANHOU, CHANG WENTANG, CHIEN
YIYUAN, CHU CHAOLlNG, LlN, H.L., ZHOU, Z,Y., QIAN, Y, ZHANG, S,G" & YUAN, lL., 1974. Cambrian trilobites. In Handbook of stratig raphy and palaeontology of southwest China, Science Press, Beijing, 82-107. (Chinese, English summary). LU YANHOU, ZHANG WENTANG, ZHU ZHAO LING, CHIEN YIYUAN & HSIANG, L.W,,1965, In Fossils of China. Chinese trilobites. Vol. 2. Science Press, Peking,363-766. (Chinese). LUCAS, I, & PREV(lT, L., 1984, Syn th�se de rap· atitepar voie bacterienne a partir de matiere organiM que phosphatee et de divers carbonates de calcium dans des eaux douce et marine nature lIes. Chem. Geol,42,101-118, LUO HUlLlN, JlANG ZHIWEN, XU ZHONGJlU, SONG XUlLlANG & XUE XIAOFENG, 1980, (On the Sinian -Cambrian boundary of Meishucun and Wangjiawan, Jinning County, Yunnan). Acta geol, sin, 1980, 95-111. (Chinese, English sum· mary), LUO HUlLlN, JlANG ZHIWEN, WU XICHE,
EARLY CAMBRIAN FOSSILS, S. AUST.
SONG XUELIANG, OUY ANG LIN et al., 1982. (The Sinian-Cambrian Boundary in Eastern Yun nan, China). People's Republic of China, 265p. (Chinese,English summary). LUO HUILlN, HANG ZHIWEN, WU X[CHE, SONG XUELIANG, OUYANG LlN, X[NG YUSHENG,LIU GUIZHI. ZHANG SHISHAN & TAO YONGHE, 1984. Sinian-Cambrian bound ary stratotype section at Meishucun, Jinning, China. People's Publishing House, Yunnan, 154p. (Chinese and English). MACKINNON,DJ.,1985. New Zealand late Middle Cambrian molluscs and the origin of Rostroconchia and Bivalvia. Alcheringa 9, 65-81. MAMBETOV, A.M., 1972. Novyy rod khiolitov iz nizhnego kembriya Malogo Karatau (severo zapadnyy Tian'-Shan'). (A new genus of hyoliths from the Lower Cambrian of Maly Karatau (northwestern Tien-Shan». Paleont. Zh. 1972(2), 140- 142. (Russian). MAMBETOV, AM,1975. Pervye nakhodki khiolitov iz nizhnego kembriya Talasskogo Alatau. (The first finds of hyoliths from the Lower Cambrian of Talasskiy Alatau). Paleont. Zh. 1975(4), 135-138. (Russian). MAMBETOV, AM.,1988. Novye predstaviteli mol Iyuskov i konodontomorf iz nizhnego i srednego kembriya Tyan'-Shanya i Malogo Karatau. (New representatives of molluscs and conodontomorphs from the Lower and Middle Cambrian of Tien-Shan and Maly Karatau). Trudy Inst. Geol. Geofiz. sib. Otd. 720,14 8--154. (Russian). MAMBETOV,A.M. & REPINA,L.N.,1979. Nizhniy kernbriy Talasskogo Alatau i ego korrelyatsiya s razrezami Malogo Karatau i Sibirskoy platformy. (The Lower Cambrian of Talasskiy Alatau and its correlation with the sections of Maly Karatau and the Siberian Platform). Trudy Inst. Geol. Geofiz. sib. Otd. 406,98--138. (Russian). MAMET, B. & ROUX, A, 1975. Algues Devonien nes et Carboniferes de la Tethys occidentale. Rev. Micropaleont. 18, 130-187. MANHEIM, F., ROWE, G.T. & JIPA, D., 1975. Marine phosphorite formation off Peru. J. sed. Pet. 45, 243-251. MAREK,L., 1963. New knowledge on the morphol ogy of Hyolithes. Sb. geol. Ved. Praha, Rada P., 1, 53-73. MAREK,L.,1967. The Class Hyolitha in the Caradoc of Bohemia. Sb. geol. Ved. Praha, Rada P. 9, 51113. MAREK, L. & GALLE, A, 1976. The tabulate coral Hyostragulum, an epizoan with bearing on hyolith ecology and systematics. Lethaia 9, 51-64. MAREK,L. & YOCHELSON,E.L.,1976. Aspects of the biology of Hyolitha (Mollusca). Lethaia 9,6582. MATTHEW, G.F., 1886. On the Cambrian faunas of Cape Breton and Newfoundland. Trans. R. Soc. Can. 4, 147-157. MATTHEW,G.F.,1894. Illustrations of the fauna of the St. John Group. Trans. R. Soc. Can. 11, MATTHEW, G.F., 1895. The Protolenus fauna. Trans. N.Y. Acad. Sci. 14,101-153. MATTHEW, G.F., 1896. Faunas of the Paradoxides
.353
Beds in eastern North America. Trans. N.Y. Acad. Sci. 15,192-247. MATTHEW, G.F.,1896. Notes on Cambrian faunas the genus Microdiscus. Am. Geol. 18. MATTHEW, G.F. 1899. Studies on Cambrian faunas. No. 3. Upper Cambrian fauna of Mount Stephen, British Columbia. The trilobites and worms. Trans. R. Soc. Can., ser. 2, 5,39-66. MATTHEW, G.F., 1899. The Etchminian fauna of Smith Sound. Newfoundland. Trans. R. Soc. Can., ser. 2, 5,97-123. MATTHEWS, S.c., 1973. Lapworthe\lids from the Lower Cambrian Strenuella limestone at Comley, Shropshire. Palaeontology 16, 139-148. MATTHEWS, S.C. & MISSARZHEVSKY, V.V 1975. Small shelly fossils of late Precambrian and early Cambrian age: a review of recent work. Q. Jl geol. Soc. Lond. 131, 289-304. M c N A M A R A, K.J 1982. H eterochrony a n d phylogenetic trends. Paleobiology 8,130-142. McNAMARA, KJ., 1985. Taxonomy and evolution of the Cainozoic spatangoid echinoid Protenaster. Palaeontology 28, 311-330. McNAMARA, KJ 1986. A guide to the nomencla ture of heterochrony.J. Paleont. 60, 4-13. McNAMARA, KJ., 1987. Taxonomy,evolution,and functional morphology of southern Australian Ter tiary hemiasterid echinoids. Palaeontology 30, 319-352. MENEGHINI, G., 1881. Nuovi trilobiti di Sardegna. Processi verb. Soc. tosc. Sci. nat. Pisa 2. (Italian). MENEGHINI, G., 1882. Fauna Cambriana dell' Iglesiente in Sardegna. Atti Soc. T oscana Sci. Natur. Pisa, Proc. Verb. 3, 158-166. MESHKOVA, N.P., 1969. K voprosu 0 paleon tologicheskoj kharakteristike nizhnekembrijskikh otlozhenij Sibirskoj platformy. (To the question of the palaeontological characteristics of the Lower Cambrian sediments of the Siberian platform). In Biostratigraphy and palaeontology of the Lower Cambrian ofSiberia and the Far East, LT. Zhurav leva, ed., Nauka,Moscow, 158-174. (Russian). MESHKOVA,N.P.,1974a. Cambroscleritida incertae sedis - novyj otryad kembrijskikh iskopaemykh. (Cambroscleritida Incertae Sedis new kind of Cambrian fossils). In Biostratigraphy and paleon tology of the Early Cambrian ofEurope and north ern Asia, I.T. Zhuravleva & A.Yu. Rozanov, eds, Nauka,Moscow,190-193. (Russian). MESHKOV A, N.P., 1974b . Khiolity nizhnego kembriya Sibirskoj platformy. (Lower Cambrian hyoliths of the Siberian Platform). Trudy Inst. Geol. Geofiz. sib. Otd. 97, 1-110. (Russian). M E S HKOV A, N.P., 198 5. N o v y e trubchatye problernatiki srednego kembriya Sibiri i Srednej Azii. (New tubular Problematica from the Middle Cambrian of Siberia and Middle Asia). Trudy Inst. Geol. Geofiz. sib. Otd. 632, 127-133. (Russian). MIERZEJEWSKI,P.,1986. Ultrastructure,taxonomy and affinities of some Ordovician and Silurian or ganic microfossils. Palaeont. pol. 47, 129-220. MILLER, J.F., 1984. Cambrian and earliest Or dovician conodont evolution,biofacies,and provin cialism. Spec. Pap. geol. Soc. Am. 196, 43-68. MISSARZHEVSKY, V.V., 1966. Pervye nakhodki .•
.•
.•
354
STEFAN BENGTSON et al.
Lapworthella v nizhnem kembrii Sibirskoj platfor my. (The first finds of Lapworthella in the Lower Caml?rian of the Siberian platform). Paleont. Zh. 196 6 (1), 13-18. (Russian). MISSARZHEVSKY, V.V., 1970. Novoye todovoye nazvaniye Tommotia Missarzhevsky, nom. novo (New generic name Tommotia Missarzhevsky, nom. nov.) Paleont. Zh. 1970(2), 100. (Russian). MISSARZHEVSKY, V.V., 1973. Konodontoobraz nye organizmy iz pogranichnykh sloev kembriya i dokembriya Si birskoj platformy i Kazakhstana. (Conodont-shaped organisms from the Precam brian-Cambrian boundary beds of the Siberian Platform and Kazakhstan). Trudy Inst. Geol. Geo fiz- sib. Otd. 49,53-57. (Russian). MISSARZHEVSKY, V.V., 1974. Novye dannye 0 drevnejshikh okamenelostyakh rannego kembriya Sibirskoj platformy. (New data on the oldest Cambrian fossils of the Siberian platform) . In 8io str atigr afiya i paleontologiya nizhnego kembriya Evropy i severnoy Azii, I.T. Zhuravleva & A.Yu. Rozanov, et al., eds, Nauka, 179-189. (Russian). MISSARZHEVSKY,V.V.,1977.Konodonty(?)i fos fatnye problematiki kembriya Mongolii i Sibiri. (Conodonts(?) and phosphatic problematica from the Cambrian of Mongolia and Siberia). In Bespoz vonochn ye Pllleozoya Mongolii, L.P. Tatarinov et al., eds, 10-19. (Russian). MISSARZHEVSKY, V.V., 1981. Rannekembrijskie khiolity i gastropody Mongolii. (Early Cambrian hyoliths and gastropods of Mongolia). Paleont. Zh. 1981(1),21-28. (Russian). MISSARZHEVSKY, V.V., 1982. Raschleneniye i korrelyatsiya pogranichnykh tolshch dokembriya i kembriya po nekotorym drevneyshim gruppam skeletnykh organismov. (Subdivision and correla tion of the Precambrian-Cambrian boundary beds using some groups of the oldest skeletal or ganisms). Bull. Mosk. Obshch. Ispyt. Prir., Otd. Geol. 57(5), 52- 67. (Russian). MISSARZHEVSKY,V.V., 1983. Stratigrafiya drev neyshikh tolshch fanerozoy a Anabarskogo massiva (Stratigraphy of the oldest Phanerozoic strata of the Anabar massif). Sov. Geol. 1983,62-73.(Russian). MISSARZHEVSKY,V.V.,1989.Drevnejshie skelet nye okamenelosti i stratigrafiya pogranichnykh tolshch dokembriya i kembriya. (Oldest skeletal fossils and stratigraphy of Precambrian and Cambrian boundary beds).Akad. NaukSSSR Trudy 443,1-238. (Russian). MISSARZHEVSKY, V.V. & GRIGOR'YEVA, N.V., 1981. Novye predstaviteli otryada Tom motiida. (New representatives of the Order Tom motiida).Paleont. Zh. 1981(1),91-97. (Russian). MISSARZHEVSKY, V.V. & MAMBETOV, A.M., 1981. Stratigrafiya i fauna pogranichnykh sloev kembriya i dokembriya Malogo Karatau. (Stratig raphy and fauna of the Precambrian-Cambrian boundary beds of Malyj Karatau). Trudy geol.lnst. Leningr. 326, 1-92. (Russian). MONTANA RI, A., 1986. Spherules from the Cretaceousrrertiary boundary clay at Gubbio,Italy: the problem of outcrop contamination. Geology 14, 1024-1026. MOORE, P.S., 1983. Geological fieldguide to the
northeast coast of Kangaroo Island. Australian Sedimentologists Group, Adelaide. MOSTLER, H., 1980. Zur Mikrofauna des Un terkambriums in der Haziraformation-Hazara, Pakistan.Annln n aturh. Mus. Wien 83, 245-257. MOSTLER, H., 1985. Neue heteractinide Spongien (Calcispongea) aus dem Unter- u n d Mittel kambrium Sudwestsardiniens. Ber. n aturw. -med. Ver.lnnsbruck 72, 7-32. MOSTLER, H., 1986. Beitrag zur stratigraphischen Verbreitung und phylogenetischen Stellung der Amphidiscophora und Hexasterophora (Hexac tinellida, Porifera). Mitt. ost. geol. Ges. 78, 319359. MOSTLER,H.,& MOSlEH-YAZDI,A., 1976.Neue Poriferen aus oberkambrischen Gesteinen der Milaformation im Elburzgebirge (Iran). Geol. Paldont. Mitt. Innsbruck 5, 1- 36. MOUNT,J.F., 1989. Re-evaluation of unconformities separating the "Ediacaran" and Cambrian Systems, South Australia. Palaios 4,366-373. MULLER, K.J., 1964. Ostracoda (Bradorina) mit phosphatischen Gehausen aus dem Oberkambrium von Schweden.Neues lb. Geol. Paltiont.Abh. 121, 1-46. MULLER, K.J., 1979. Phosphatocopine ostracodes with preserved appendages from the Upper Cambrian of Sweden. Lethaia 12,1-27. MULLER, K.L & MILLER, LF., 1976. The problematic microfossil, Utahphos pha from the Upper Cambrian of the western United States. Lethaia 9, 391- 395. MULLER, Kl., NOGAMI, Y. & LENZ, H., 1974. Phosphatische Ringe als Mikrofossilien im Alt paliiozoi kum.Pala eontographicaA 146,79-99. NARBONNE, G.M., MY ROW, P.M., LANDING, E. & ANDERSON, M.M., 1987. A c a n d i d ate stratotype for the Precambrian-Cambrian bound ary, Fortune Head, Burin Peninsula, southeastern Newfoundland. Can. J. EarthSci. 24, 1277-1293. NASLUND, H.R., OFFICER, c.B. & JOHNSON, G.D., 1986. Microspherules in Upper Cretaceous and lower Tertiary Clay layers at Gubbio, Italy. Geology 14,923-926. N A Z A R O V , B . B . & P O P OV, L . E . , 1 9 8 0 . Stratigrafiya i fauna kremnisto-karbonatn ykh tolshch ordovika Kazakhstana. (Stratigraphy and fauna of the Ordovician silice ous-carbonate deposits of Kazakhstan). Trudy geol.lnst. Leningr. 331. 1-190. (Russian). NOWLAN, G.S., NARBONNE, G.M. & FRITZ, W.H., 1985. Small shelly fossils and trace fossils near the Precambrian-Cambrian boundary in the Yukon Territory, Canada. Lethaia 18 233-256. 1. ODIN, G.S., GALE, N.H. & DORh, F., 1985. Radiometric dating of late Precambrian times. Mem. geol. Soc. Lond. 10, 65-72. OFFLER,R. & FLEMING,P.D.,1968.A synthesis of folding and metamorphism in the Mount Lofty Ranges, South Australia. l. geol. Soc. Awl. 1�. 245-266. OKADA, Y., 1981. Development of cell arrangement in ostracode carapaces. Paleobiology 7, 276-28Q. OKADA, Y., 1982. Structure and cuticle formation of the reticulated carapace of the ostracode Bicor-
EARLY CAMBRIAN FOSSILS, S. AUST.
.. nucythere bisanensis.Lethaia 15,85-1Ol. OPIK,AA.,1967. The Ordian stage of the Cambrian and its Australian Metadoxididae. Bull Bur. Miner. Resour. Geo!. Geophys.Aust. 92, 133-168. OPIK, A.A., 1968. Ordian (Cambrian) Crustacea Bradoriida of Australia. Bull. Bur. Miner. Resour. .. Geol. Geophys.Aust. 103, 1-45. OPIK,AA,1970.Redlichiaof the Ordian (Cambrian) of Northern Australia and New South Wales. Bull. Bur. Miner. Resour. Geol. Geophys.Aust. 114, 167. OPIK, A.A., 1975a. Templetonian and Ordian xystridurid trilobites of Australia. Bull. Bur. Miner. .. Resour. Geol. Geophys.Aust. 121, 1-84. OPIK, AA, 1975b. Cymbric Vale fauna of New South Wales and Early Cambrian biostratigraphy. Bull. Bur. Miner. Resour. Geol. Geophys.Aust. 159, 1- 78. PALMER, A.R., 1968. Cambrian trilobites of east central Alaska. Pro! Pap. U.S. geol. Surv. 559-B, B1- B115. PALMER, AR., 1977. Biostratigraphy of the Cam brian System - a progress report.Ann. Rev. Earth Planet. Sci. 5, 13-33. PARKIN,L.W. & KING, D., 1952. Geological Atlas of South Australia, Copley sheet. 1 inch/1 mile. (1:63,360). Geol. Sury. S. Aust., Military Survey Map Reference No. 686. Zone 5. PEEL, J.S., 1979. Anatolepis from the Early Or dovician of East Greenland - not a fishy tail. Gr�nlands geol. Under., Rapp. 91,111-115. PEEL,1.S., 1987. Yochelcionella americana (Mollus ca) from the Lower Cambrian of Newfoundland. Can. I. Earth Sci. 24, 2328-2330. PEEL,1.S., 1988. Molluscs of the Holm Dal Forma tion (late Middle Cambrian),central North Green land Meddr Grlf'nland, Geosci. 20,145-168. PEEL,1.S & BLAKER,M.R.,1988. The small shelly fossil Mongolitubulus from the Lower Cambrian of central North Greenland. Grlf'nlands geol. Under., Rapp. 137, 55-60. PEEL,1.S. & YOCHELSON,E.L., 1987. New infor mation on Oelandia (Mollusca) from the Middle Cambrian of Sweden. Bull. geol. Soc. Denmark 36, 263-273. PEI FANG, 1985. First discovery of Yochelcionella from the Lower Cambrian of China and its sig nificance. Acta micropaleont. sin. 2, 395-400. (Chinese,English summary). PICKETT,1. & JELL,PA,1983. Middle Cambrian Sphinctozoa (porifera) from New South Wales. Mem.Ass.Australas. Palaeontols 1, 85-92. PING, CHEN, 1984. Discovery of Lower Cambrian small shelly fossils from lijiapo, Yichang, west Hubei and its significance. Prof. Pap. Stratig. Palaeont. 13,61-64. POCOCK,K.l.,1964. Estaingia, a new trilobite genus from the Lower Cambrian of South Australia. Palaeontology 7, 458-471. POCOCK,K.l., 1970. The Emuellidae,a new family of trilobites from the Lower Cambrian of South Australia. Palaeontology 13, 522-562. POCOCK,K.J., 1974. A unique case of teratology in trilobite segmentation.Lethaia 7, 63-66. POJETA, J., 1975. Fordilla troyensis Barrande and .
355
early pelecypod phylogeny. Bull. Am. Paleont.67, 363-384. POJETA,J. & RUNNEGAR, B.N., 1976. The paleon tology of rostroconch mollusks and the early history of the Phylum Mollusca. Pro! Pap. U.S. geol. Sury. 968,1-88 . POKROVSKAYA, N.V.,1959. Trilobitovaya fauna i stratigrafiya kembriyiskikh otlozheniy Tuvy. (Trilobite fauna and stratigraphy of Cambrian deposits of Tuva). Trudy geol. Inst. Leningr. 27, 1-198. (Russian). POKROVSKAYA, N.V., 1960. Order Miomera. In Osnovy Palaeontologii. Chlenistonogie trilo bitoobraznye i rakoobraznye. (Principles of pal a e o n t o lo g y . A r t h r o p o d s, t r i l ob i t e s a n d crustaceans). Chernysheva, N.V., ed. Akademii Nauk, SSSR, Moskva, 8, 54- 61.(Russian). POKROVSKAYA, N.V.,1967. Klass Trilobita (Class Trilobita). In Fauna nizhnego kembriya Tuvy (The Lower Cambrian fauna of Tuva), A.Yu Rozanov, ed., Izdatelstvo Nauka, Moscow, 108-140. (Rus sian). POULSEN, c., 1942. Nogle hidtil uklendte Fossiler fra Bornholms Exsulanskalk. (Some hitherto un known fossils from the Exsulans Limestone of Bornholm). Meddr dansk geol. Foren. 212-235. (Danish, English summary). POULSEN, C., 1967. Fossils from the Lower Cam brian of Bornholm. Danske Vidensk. Selskab, Matematisk-Fysiske Meddr 36,1-48. POULSEN,V., 1963. Notes on Hyolithellus Billings, 1871, Class Pogonophora Johannson, 1937. Bioi. Meddr, Kong. Danske Videns!c. Selskap 23(12),115. PREV6T, L. & LUCAS, J., 1986. Microstructure of apatite replacing carbonate in synthesized and natural samples. I. sed. Pet. 56,153-159. QIAN JIANXIN & XIAO BING, 1984. (An early Cambrian small sheIly fauna from Aksu-Wushi Region, Xinjiang). Pro! Pap. Strat. Palaeont. 13, 65-90. (Chinese,English summary). QIAN YI, 1977. (Hyolitha and some problematica from the Lower Cambrian Meishucunian Stage in central and southwestern China). Acta palaeont. sin. 16, 255-275. (Chinese, English summary). QIAN YI, 1978a. (The early Cambrian hyolithids in central and southwest China and their stratigraphi ca] significance). Mem. Nanjing Inst. Geol. Palaeont. 11,1-38. (Chinese, English summary). QIAN YI, 1978b. Palaeontological descriptions, Sinian. In Stratigraphy and palaeontology from Sinian to Permian in the eastern part of the Yangtze Gorge. Hubei Province, Geological Department, Yangtze Gorge Working Group. Geological Publishing House, Beijing, 109-138. (Chinese). QIAN YI, 1984. (Several groups of bizarre sclerite fossils from the earliest Cambrian in eastern Yun nan). Bull. Nanjing Inst. Geol. Palaeont. 6, 85-99. (Chinese, English summary). QIAN YI & BENGTSON, S., 1989. Palaeontology a n d b i o stratigraphy of the Early Cambrian Meishucunian Stage in Yunnan Province, south China. Fossils and strata 24,1-156. QIAN YI, CHEN MENGE & CHEN YIYUAN, 1979. (Hyolithids and other small shelly fossils
356
STEFAN BENGTSON et al.
from the Lower Cambrian Huangshandong Forma tion in the eastern part of the Yangtze Gorge), Acta palaeont. sin.IB, 207-230. (Chinese,English sum mary). QIAN YI & YINGONGZHENG,1984a. (Small shel ly fossils from the lowest Cambrian in Guizhou). Prof. Pap. Strat. Palaeont. 13, 91-123. (Chinese, English summary). QIAN YI & YIN GONGZHENG, 1984b. (Zhijinit idae and its strati graphical significance). Acta palaeont. sin. 23,215-223. (Chinese, English sum mary). QIAN YI & ZHANG SHIBEN, 1983. (Small shelly fossils from the Xihaoping Member of the Tangy iog Formation in Fangxian county of Hubei province and their stratigraphical significance). Acta palaeont. sin. 22, 82-94. (Chinese, English summary). RAILSBACK,L.B. & ANDERSON, T.F., 1987. Con trol of Triassic seawater chemistry and temperature on the evolution of post-Paleozoic aragonite secreting faunas. Geology 15, 1002-1005. RASE1TI, F., 1952. Revision of the North American trilobites of the family Eodiscidae.l. Palaeont. 26, 434-451. RASETTI,F., 1972. Cambrian trilobite faunas o f Sar· dinia. Aui Acead. naz. Lineei Memorie, Classe di -scienze fisiehe e matematische, ser. 8. 11, 1-100. RAYMOND, P.E., 1913. On the genera of the Eodis cidae. Ottawa Nat. 27, 101-106. REDLICH, K., 1899. The Cambrian fauna of the eastern Salt Range. Mem. Geol. Surv. India, Pal aeont. Indiea, n.s. I, 1-13. REIF, W.E., 1968. Schwammreste aus d e m oberen Ordovizium von Estland und Schweden.NeuesJb. Geol. PaWont. Mh. 1968(12), 733-744. REIF, W.E., 1974. Morphogenese und Musterbildung des Hautzahnchen·Skelettes von Heterodontus. Lethaia 7, 25-42. REPETSKJ, J.E.,1981. An Ordovician occurrence of Utahphospha Muller & MiIler.J. Paleont. 55,395400. REPINA, L.N., 1956. Materialy po paleontologii. Novye semeistva i rody. (Materials for paleontol· ogy. New families and genera).lzd. Vses. naehno issled. Geol.l nst., n.s., 12" 145-147. (Russian). REPINA,L.N., 1960. Kompleksy trilobitov nizhnego i srednego kembriya zapadnoi chasti vostochnogo Sayana. (Complexes of trilobites of the Lower and Middle Cambrian of the western part of the Eastern Sayan). Reg. Stratigr. SSSR 4,171-232. (Russian). REPINA, L.N., 1966. Trilobity nizhnego kembriya yuga Sibiri. (nadsemeistvo Redlichioidea), I. (Trilobites of the Lower Cambrian of southern Siberia. Superfamily Redliehioidea). lost. Geol. Geofiz. sib. Otd.,Moscow, 204p. (Russian), REPINA, L.N., 1969. Trilobity nizhnego i srednego k e m b r i y a y u g a S i b i r i . (nadsemeistvo Red lichioidea), 2. (Trilobites of the Lower and Middle Cambrian of southern Siberia. Superfamily Red· liehioidea). Trudy Inst. Geol. Geojiz. Sib. Otd. 67. (Russian). R EPINA, L.N., 1972. Trilobity Tarynskogo Gorizonta razrezov nizhnego Kembriya r. Suk· harikhi (Igarskii raion). (Trilobites of the Taryn -
Gorizont in the Lower Cambrian section of the Sukharikhi River, Igarskii Region). In Problemy biostratigrafi'i i paleont(Jlogii nizhnego Kembriya Sibiri. (Problems in biostratigraphy and palaeon tology of the Lower Cambrian of Siberia). Zhurav· leva, I.T., ed. Sib. otd. lost. Geol. Geofiz., Akad. nauk SSSR, 184-216. (Russian). REPINA, L.N., KHOMENTOVSKY, V.V., ZHURAVLEVA,I.T. & ROZANOV,A. Yu,1964. Biostratigrafiya nizhnego kembriya Sayano-Al tayskoy skladehato yoblasti. (Biostratigraphyofthe Lower CambrianQf the Sayan-Altay folded region). Izdatelstvo,Moscow, 1-364. (Russian). REPINA,L.N.,LAZARENKO, N.P., MESHKOVA, N.P., KORSHUNOV, V.I., NIKIFOROV, N.1. & AKSARINA, N.A., 1974. Biostratigrafiya i fauna nizhnego kembriya Kharaulakha (khr. Tuora�Sis), (Biostratigraphy and fauna of the Lower Cambrian of Kharaulakh (Tuora·Sis range»). Trudy I nst. Geol. Geofiz. sib. Old. 235, 1-299. (Russian). REPINA, L.N., YASKOVICH, B.V., AKSARINA, N.A., PETRUNINA, S.E., PONIKLENKO, I.A., RUBANOV, D.A.,BOLGOVA,G. V., GOLIKOV, A.N., HAJRULLINA, T.1. & POSOKHOVA, M.M., 1975. Stratigrafiya i fauna nizhnego paleozoya severnykh predgoriy Turkestanskogo i Alayskogo khrebtov (yuzhniy Tyany-shani), (Stratigraphy and fauna of the lower Palaeozoic of the northern submontane belt of Turkestan and Alai ridges [southern Tien-Shan)), Trudy Inst. Geol. Geofiz. sib. Otd. 278, 1-351. REPINA, L.N, & ROMANENKO, E.V., 1978. Trilobity i stratigraphiya nizhnego kembriya Al taya. (Trilobites and stratigraphy of the Lower Cambrian of Altai). Trudy Inst. Geol. Geofiz. sib. Otd. 382, 1-304. (Russian). RESSER, C.E., 1939. The Ptarmigania strata of the northern Wasatch Mountains. Smithson. mise. Collns 98(24), 1-72. RESSER, C.E. & ENDO,R.,1937. Deseription of the fossils. Maneh. sci. Mus. Bull. 1, 103-301, 370434. RICHTER, R. & E., 1940. Die Saukianda-Stufe von Andalusien.Abh. senekenb. naturforseh. Ges., 450, 1-88. RICHTER, R. & E., 1941. Die Fauna des Unter Kambrium von Cala in Andalusien.Abh. senekenb. naturforseh. Ges., 455, 1-90 . RIDING, R., 1982, Cyanophyte calcification and changes in ocean chemistry. Nature 299, 81 4-815. RIEGER,R.M. & STERRER, W., 1975. New spieular skeletons in Turbellaria, and the occurrence of spicules in marine meiofauna. Zeit. zool. Syst. Ev olutionsfors. 13,207-278. RIGBY, J.K., 1975. Some unusual hexactinellid sponge spicules from the Cambrian Wilberns For mation of Texas.l. Paleont. 49,412-415. RIG BY, J.K., 1978. Porifera of the Middle Cambrian Wheeler Shale, from the Wheeler Amphitheater, House Range, in western Utah. 1. Paleont. 52, 1325-1345. RIGBY,J.K., 1983.FossiIDemospongia. Univ. Tenn., Dept. geol. Scis, Studs Geol. 7, 12-39. RIG BY ,J.K., 1986. Sponges of the Middle Cambrian Burgess Shale (Middle Cambrian),British Colum-
EARLY CAMBRIAN FOSSILS, S. AUST.
bia. Palaeontogr. can. 2, 1-105. RIGBY,J.K. & NlTECKI, M.H., 1975. An unusually well preserved heteractinid sponge from the Pen nsylvanian of Illinois and a possible classification and evolutionary scheme for the Heteractinida. 1.
Paleont. 49, 329-339. RIGBY, J.K. & TOOMEY, D.F., 1978. A distinctive sponge spicule assemblage from organic buildups
in the Lower Ordovician of southern Oklahoma. 1. Paleont. 52, 501-506. ROSEN, S., 1919. Uber einige neue Problematica in einem fossilfiihrenden Kalkstein aus dem nord schwedischen Hochgebirge. Bull. geol. Instn Univ.
Uppsala 16, 159-168. ROWELL,AJ.,1982. The monophyletic origin of the Brachiopoda. Lethaia 15, 299-307. ROZANOV, AYu., 1986. Problematica of the early Cambrian. In Problematic fossil taxa, A Hoffman & M.H. Nitecki,eds,Oxford University Press,New York,87-96. ROZANOV, A. Yu. & MISSARZHEVSKY, V.V., 1966. Biostratigrafiya i fauna nizhnikh gorizontov kembriya. (Biostratigraphy and fauna of Lower Cambrian horizons). Trudy geol.lnst. Moscow 148, 1- 126. (Russian). ROZANOV, A.Yu., MISSARZHEVSKY, V.V., VOLKOVA, N.A., VORONOVA, L.C., KRYLOV, LN., KELLER, B.M., KOROLYUK, LK., LENDZION, K., MICHNIAK, R., PYK HOVA, N.G., & SIDOROV, AD., 1969. Tom motskij yarus i problem a nizhnej grantisy kembriya. (The Tommotian Stage and the Cam brian lower Boundary problem). Trudy geol. Inst. Moscow, 206, 1-380. (Russian, English edition, 1981, Amerind. Publishing Co.,New Delhi,359p). ROZANOV,A Yu. & SOKOLOV,B.S. (eds),1984. Yarusnoe raschlenenie nizhnego kembriya, strat igrafiya. (Lower Cambrian stage subdivision, strat igraphy). Nauka, Moscow,184p. (Russian). RUDAVSKAYA, V.A. & VASIL'EVA, N.L, 1984. Pervye nakhodki lyukatiskikh akritarkh v nizhnem kembrii Chekurovskogo razreza vostochnoy Sibiri. (First finds of Lukati acritarchs from the Lower Cambrian Chekurovka section in eastern Siberia). Dokl. Akad. Nauk SSSR 279, 1454-1456. (Rus sian). RUDWICK, M.1.S., 1970. Living and fossil brach iopods, Hutchinson, London, 1-199. RUNNEGAR,B.,1981. Muscle scars,shell form and torsion in Cambrian and Ordovician univalved mol luscs. Lethaia 14, 311-322. RUNNEGAR, B., 1983. Molluscan phylogeny revisited.Mem.Ass.Australas. Palaeontols 1, 121144. RUNNEGAR, B., 1985a. Early Cambrian endolithic algae.Alcheringa 9, 179-182. RUNNEGAR, B., 1985b. Shell microstructures of Cambrian molluscs replicated by phosphate. AI cheringa 9, 245-257.
RUNNEGAR, B. & BENTLEY, C., 1983. Anatomy, ecology and affinities of the Australian early Cambrian bivalve Pojetaia runnegari J e l l . 1. Paleont. 57, 73-92. RUNNEGAR, B. & JELL, P.A., 1976. Australian Middle Cambrian molluscs and their bearing on
357
early molluscan evolution.Alcheringa 1, 109-138. RUNNEGAR, B.N. & JELL, P.A, 1980. Australian
Middle Cambrian molluscs: corrections and addi tions. Alcheringa 4, 111-113. RUNNEGAR, B.N. & POJETA, J., 1974. Molluscan phylogeny: the palaeontological viewpoint. Science 186, 311-317. R U N N E G A R , B. & P O J E T A , J . , 1 9 8 0 . T h e monoplacophoran mollusk Yochelcionella iden tified from the Lower Cambrian of Pennsy Ivania. 1. Paleont. 54, 635-636. RUNNEGAR, B. & POJETA, J., 1985. Origin and diversification of the Mollusca. In The Mollusca,
vol. 10, E.R. Trueman & M.R. Clarke, eds, Academic Press,Orlando,1-57. RUNNEGAR, B., POJETA, J., JR., MORRIS, N.1., TAYLOR, J.D., TAYLOR, M.E. & McCLUNG, G.,1975. Biology of the Hyolitha. Lethaia 8,181191. SANDGREN, C.D., 1983. Survival strategies of chrysophycean flagellates: reproduction and the formation of resistant resting cysts. In Survival strategies of the algae, G.A Fryxell, ed., Camb ridge University Press,Cambridge,23-48. SAV AZZI, E., 1986. Burrowing sculptures and life habits in Paleozoic Iingulacean brachiopods. Paleobiology 12, 46-63. SCOTT, H.W.,1961. Orientation of ostracode shells. In Treatise on invertebrate paleontology, Part Q,
Arthropoda 3, R.C. Moore, & C.W. Pitrat, eds, Geological Society of America, Boulder, and University of Kansas Press, Lawrence, 044-Q47. SDZUY, K., 1958. Neue trilobiten aus dem Mit telkambrium von Spanien. Senckenberg. leth. 39, 235-253. SDZUY, K., 1959. Die unterkambrische Trilobiten Familie Dolerolenidae. Senckenberg. leth. 40, 389407. SDZUY, K., 1961. Das Kambrium Spaniens (teil 11: Trilobiten). Abh. math. -naturw. KI. Akad. Wiss. Mainz. 7 219-312. SDZUY, K., 1969. Unter- und mittelkambrische Porifera (Chancelloriida und Hexactinellida). Paliiont. Z. 43, 115-147. SDZUY, K., 1971. Acerca de la carrelacion del Cambrico Inferior en la Peninsula Iberica. In Publ. I Congr. Hisp. LusoAmer. Geol. Econ., vol.2, sec tion 1,Madrid,753-768. SDZUY, K. , 1978. The Precambrian-Cambrian boundary beds in Morocco (Preliminary Report). Geol. Mag. 115,83-94. SEPKOSKI, J.1., 1981. A kinetic model of Phan erozoic taxonomic diversity 11. Early Phanerozoic families and multiple equilibria. Paleobiology 5, 222-251. SHABANOV, YU. YA., A S TASHKIN, V.A., PEGEL'T.B., EGOROVA,L.L,ZHURAVLEVA, LT., PEL'MAN, YU.L., SUNDUKOV, V.M., STEPANOVA,M.B.,SUKHOV,c.c., et al., 1987. Nizhniy paleozoy yugo-zapadnogo sklona Ana barskoy anteklizy. Nauka, Novosibirsk, 1-207. (Russian). SHALER,N.S. & FOERSTE,AF.,1888. Preliminary description of North Attleborough fossils. Bull. Mus. Comp. Zool. 16,27-41.
358
STEFAN BENGTSON et al.
SHU DEGAN & CHEN LING. 1988. Discovety of Early Cambrian Radiolaria and its significance. Scientia sin. B, 1988(8),881-886. (Chinese). SIGNOR, P.W., MOUNT, l.F. & ONKEN, B.R., 1987. A preMtrilobite Shelly fauna from the White Inyo region of eastern California and western Nevada.J. Paleont. 61,425-438. SINGH,P. & SHUKLA, S.D., 1981. Fossilsftom the Lower Tal: their age and its bearing on the stratig. raphy of the Lesser Himalayas. Geosciencelournal 2,157-176. SOKOLOV,B.S. & ZHURAVLEVA,I.T.,eds, 1983. Yarusnoe raschlenenie nizhnego kembriya Sibiri. Atlas okamenelostej. (Lower Cambrian stage sub division of Siberia. Atlas of fossils). Trudy Inst. Geol. Geofiz. sib. Otd. 558,1-216. (Russian). SOUTH GATE, P . , 1 9 8 6 . Cambtian p h o sctete profiles, coated grains,and microbial processes in phosphogenesis: Georgina Basin,Australia. J. sed. Pet. 56, 42�-44 1. S P I Z H A R S K I , T . N . , Z H U R A V L E V A , I.T., REPINA, L.N., ROZANOV, A.Yu., CHERNY SHEVA, RYe. & ERGALIEV, G.H., 1986. The stage scale of the Cambrian system. Geol. Mag. 123,387-392. SPJELDNAES, N., 1957. The Middle Otdovician of the Oslo Region. 8. Brachiopods of the suborder Strophomenida.Norsk geol. Tidsskr. 37, 1-214. SPRIGG, R.e., 1955. The Point Marsden Cambrian Beds, Kangaroo Island, South Australia. Trans. R. Soc. S.Aust. 78, 165-168. STANLEY, S.M., 1970. Relation of shell form to life habits in the Bivalvia (Mollusca). Mem. geol. Soc. Am. 125, 1-296. STANTON,R.J.,1 967. Radiosphaerid calcispheres in North America and remarks on calcisphere clas� sification. Micropaleontology 13,465-472. S U N YUNCHA, 1963. On the occurrence o f Xystridura fauna from Middle Cambrian Hainan Island and its significance. Acta palaeont. sin. 11, 608-609. SUVOROVA,N.P.,1960. Ttilobity kembtiya vostoka sibiriskoi platformy,2: Olenellidy - Granulyariidy. (Trilobites of the Cambrian of the eastern Siberian Platform. 2: Olenellidae - Granulariidae). Trudy palaeont. Inst. 84, 1-238. (Russian). SUVOROVA, N.P.,1964. Ttilobity kotineksokhoidy i ikh istoricheckoe razvitie (Corynexochidtrilobites and their historical development). Trudy palaeont. Inst. 1 03, 1-319. SYSOEV,V.A., 1958. Nadottyad Hyolithoidea. (The Superorder Hyolithoid ea). In Osnovy Paleon�
tologii. Mollyuski golovonogie. P. Ammonoidei (Tseratity i ammonity). Vnutrirakovinnye. Priloz� henie: Konikonkhii, A. Yu Orlov,ed.,Gosgeoltek� hizdat,Moscow. SYSOEV, V.A., 1962. Chiolity kembriya severnogo
sklona Aldanskogo shchita. (Cambrian hyoliths from the northern slope of the Aldan Shield). Nauka,Moscow, 1-66. (Russian). SZANIAWSKI, H., 1982. Chaetognath gtasping spines recognized among Cambrian protocono donts. J. Paleont. 5 6,806-810. SZANIAWSKI,H.,1983. Structure of protoconodont elements. Fossils andStrata 15, 21-27.
TANABE, K. & FUKUDA, Y., 1983. Buccal mass structure ofthe Cretaceous ammonite Gaudryceras. Lethaia 1 6 ,249-256. TATE, R . , 1892. The Cambrian fossils of South Australia. Trans. R. Soc. S.Aust.15, 183-189. TAYLOR, T.G., 1910. The Archaeocyathinae from the Cambrian of South Australia with an account of the morphology and affinities of the whole class. Mem. R. Soc. S. Aust. 2,55-188. TEPPER,O., 1879. An introduction to the cliffs and rocks at Ardrossan, Yorke's Peninsula. Trans. R. Soc. S. Ausl. 2, 77. THOMSON, B . P . , 1 9 6 9 . Adelaide Map Sheet, Geological Atlas of South Australia, 1:250,000 series. Geol. Surv. Sth Aust.,Adelaide. THOMSON, B.P. & HORWITZ, A.B., 1962. Barker
Map Sheet, Geological Atlas of South Australia,
1 :250,000 series. Geol. Surv. Sth. Aust.,Adelaide. THOMSON, B.P.,DAIL Y,B.,COATS,R.P. & FOR BES, B.G., 1976. Excursion Guide No. 33A Late Precambrian and Cambrian geology of the Adelaide 'Geosyncline' and Stuart Shelf, South Australia.
XXVth Int. geol. Congr. Sydney Excur. Guide 33A, 1-53. TRUEMAN,E.R. & WONG,T.M., 1987. The tole of the coelom as a hydrostatic skeleton in Iingulid brachiopods.J. Zool., Lond. 213, 221-232. VALENTINE, lW., 1973. Coelomate superphyla. Syst. Zool. 22, 97-102. VAL'KOV, A.K., 1975. Biostratigrafiya i khiolity
kembriya severo-vostoka Sibirskoj platformy. (Cambrian biostratigraphy and hyoliths of the north�east Siberian platform). Nauka, Moscow, 139p. (Russian). VAL 'KOV, A.K., 1982. Biostratigriya nizhnego
kembriya vostoka Sibirskoj platformy (Uchuro Majskij rajon). (Biostratigraphy of the lower Cambrian of t h e eastern Siberian platform (Uchura-Maya Region)). Nauka, Moscow, 91p. (Russian). VAL'KOV, A.K., 1987. Biostradgrafiya nizlrnego
kem briya vostoka Sibirskoj platformy. (Lower Cambrian biostratigraphy of the eastern Siberian Platform). Nauka, Moscow, 137p. (Russian). VAL'KOV, A.K. & SYSOEV, V.A., 1970. Angus tiokreidy kembriya Sibiri. (Cambrian angus� tiochreids of Siberia). In Stratigrafiya i paleont�
ologiya proterozoya i kembriya vostoka Sibirskoj platform, AK. Bobrov, ed., Yakutskoe Knizhnoe Izdatel'stvo,Yakutsk, 94-100. (Russian). VAN NAME, W.G., 1945. The North and Soutb American ascidians. Bull. Am. Mus. nat. Hist.84, 1-476. VASIL'EVA, N.I.,1985. K sistematike otryada Chan� celloriida Walcott, 1920 (incertae sedis) iz nizhne� kembriyskikh otlozhenij vostoka Sibirskoy plat¥ formy. (On the systematics of the Order Chancel· loriida Walcott, 1920 (incertae sed is) from Lower Cambrian deposits of the western part of the Siberian Platform). Trudy Inst. Geol. Geofiz. sib. Otd. 632,1 15-126.(Russian). VASIL'EVA, N.I., 1986. Novyj tod anabaritid iz nizhnego kembriya Sibirskoj platformy. (A new anabaritid genus from the Lower Cambrian of the Sibetian platform). Paleont. Zk 1986(2), 103-104.
EARLY CAMBRIAN FOSSILS, S. AUST.
(Russian). VASIL'EVA,N.I. & SAYUTINA, T.A.,1988. Mor fologicheskie raznoobrazie skleritov khantsellorij. (The morphological diversity of chancelloriid sclerites). Trudy Inst. Geol. GeoJiz. sib. Otd. 720, 190--198. (Russian). VOGEL, K, GOLUBIC, S. & BRETT, C.E., 1987. Endolith associations and their relation to facies distribution in the Middle Devonian of New York State, U.S.A.Lethaia 20,263-290. VON DER BORCH, C.C., 1980. Evolution of Late Proterozoic to early Paleozoic Adelaide fold belt, Australia: comparisons with post- Permian rifts and passive margins. Tectonophysics 70, 115-134. V O R O N I N, Y U . I . , V O R O N OV A , L . G . , G R I GOR'EVA, N.V., DROZDOVA, N.A., ZHEGA L L O, E . A . , ZHURAVLEVA, LT., RAG O Z I N A , A . L . , R O Z A N O V , A . Y U , SA YUTINA, T.A., SYSOEV, V.A. & FONIN, V.D., 1982. Granitsa dokembriya i kembriya v geosinklinal'nykh oblastyakh (opornyj razrez Salany-Gol, MNR). (The Precambrian/ Cambrian boundary in the geosynclinal areas (the reference section of Salany-Gol, MPR». Trudy Sovmest. Sovet.-Mongol. paleont. Eksped.18, 1-150. (Rus sian). VORONOVA, L.G. & MISSARZHEVSKY, V.V., 1969. Nakhodki vodoroslej i trubok chervej v pogranichnykh sloyakh kembriya i dokembriya na severe Sibirskoy platformy. (Discoveries of algae and worm tubes in Precambrian-Cambrian bound ary beds of the northern Siberian Platform). DokI. Akad. Nauk. SSSR 184, 207-210. VOSTOKOVA,V.A.,1962. Kembriyskie gastropody Sibirskoy platform y i Taymyra. (Cambrian gastropods from the Siberian Platform and Taimyr). Sb. St. Paleont. i Strat. 28 51-74. (Russian). WAINWRIGHT,S.A.,BIGGS,W.D.,CURREY,J.D. & GOSLINE, J.M., 1976. Mechanical design in organisms, Edward Arnold, London & Halstead Press, New York, 423p. WALCOTT, C.D., 1889. Description of new genera and species of fossils from the Middle Cambrian. Proc. U.S. natn. Mus. 11,441-446. WALCOTT, C.D., 1890. Descriptive notes of new genera and species from the Lower Cambrian or Olenellus Zone of North America. Proc. U.S. natn. Mus. 12,33-46. WALCOTT,C.D.,1905. Cambrian faunas of China. Proc. U.S. not. Mus. 29,1-106. WALCOTT,C.D.,1911. Middle Cambrian annelids, Smithson. misc. Collns 57,109-144. WALCOTT, C.D., 1913. The Cambrian faunas of China. Pubis Carnegie Instn 54(3),3-276. WALCOTT,C.D., 1916. Cambrian trilobites. Smith son. misc. Collns 64, 303-457. WALCOTT,C.D.,1920. Middle Cambrian Spongiae. Smithson. misc. Collns 67, 261-364. WALTER, M.R., 1967. Archaeocyatha and the biostratigraphy of the Lower Cambrian Hawker Group,South Australia.]. geol. Soc. Aust. 14,139152. WANG HONGZHEN, 1941. Note on Chungitsuu phosphate deposit. Bull. geol. Soc. China 21, 6970. ,
359
WANG YANGENG, YIN GONGZHENG, ZHENG SHUFANG, QIAN YI et al., 1984a. (The Sinian Cambrian boundary in central, western and north ern parts of Guizhou). Bull. Inst. Geol., Chinese Acad. geol. Scis 10,91-110 (Chinese). WANG YANGENG, YIN GONGZHENG,ZHENG SHUFANG, QIAN YI et al., 1984b. (Biostratig raphy of the Sinian-Cambrian Boundary in the Yangzi area of Guizhou). In The upper Pre cambrian and Sinian-Cambrian boundary in Guiz hou, Wang Yangengetal.,eds,People's Publishing House, Guizhou, 1-31 (Chinese, English sum mary). WEBB, B.P. & VON DER BORCH, C., 1962. Wit lochra Map Sheet, Geological Atlas of South Australia, 1 mile series. GeoI. Surv. Sth. Aust., Adelaide. WERLE,N.G., FREST,T. J. & MAPES,R.H.,1984. The epizoan Phosphannulus on a Pennsylvanian crinoid stern from Texas. ]. Paleont. 58, 11631166. WESTERGARD,A.H.,1949. Opsidiscus, new name re placing Aulacodiscus Westergll.rd, 1946. 'Geo/. For. Stockh. Forh. 71,606. WHITEHOUSE,F.W.,1936. TheCambrian faunas of north-eastern Australia: Part 1, Stratigraphic out line; Part 2, Trilobita (Miomera). Mem. Qd. Mus. 11,59-112. WHITEHOUSE,F.W.,1939. The Cambrian faunas of north-eastern Australia: Part 3, the polymerid trilobites. Mem. Qd. Mus. 11,179-282. WIMAN, C., 1903. Studien liber das Nordbaltische Silurgebiet.1. Olenellussandstein,Obolussandstein und Ceratopygeschiefer. Bull. geol. Inst. Univ. Up sala 6,12-76. WINGSTRAND, K.G., 1985. On the anatomy and relationships of Recent Monoplacophora. Galathea Rep. 16, 1-94. WOOD,A.,1957. The type-species of the genus Gir vanella (calcareous algae). Palaeontology 1, 2228. WOODWARD, H., 1884. Note on the remains of trilobites from South Australia. Geol. Mag., n.s., dec. 3, 1, 372-374. WOPFNER, H., 1970. Early Cambrian palaeogeog raphy, Frome Embayment, South Australia. Bull. Am. Ass. Petrol. Geol. 54, 2395-2409. WOPFNER, H., 1972. Depositional history and tec tonics of South Australian sedimentary basins. Mineral Resour. Rev., Sth Aust. 133, 32-50. WRIGHT, A.D., 1979 . Brachiopod radiation. Syst. Ass. Spec. Vol. 12,235-252. (Academic Press,Lon don). WRONA, R., 1982. Early Carnbrian phosphatic microfossils from southern Spitsbergen (Homs hund region). Palaeont. pol. 43, 9-16. W R O N A , R . , 1 9 8 7 . C a m b r i a n m i cr o f o s s i l Hadimopanella Gedik from glacial erratics in west Antarctica. Palaeont. pol. 49, 37-48. XIAO LIGONG & ZHOU BENHE, 1984. (Early Cambrian Hyolitha from Huainan and Huoqiu County in Anhui Province). Prof. Pap. Strat. Palaeont. 13, 141-151.(Chinese). XING YUSHENG & LUO HUILIN, 1984. Precambrian-Cambrian boundary candidate,
360
STEFAN BENGTSON et al.
Meishucun, Jining, Yunnan, China. Geol. Mag. 121, 143-154. XING YUSHENG, DING QIXIU, LUO HUlLlN,HE . TINGGUI & WANG YANGENG, 1984a. The Sinian-Cam brian boundary of China and its related problems. Geol. Mag. 121,155-170. XING YUSHENG, DING QIXIU, LUO HUILlN,HE TINGGUI,WANG YANGENG et al., 1984b. (The Sinian-Cambrian boundary of China). Bull. Inst. G eol., Chi nese Acad. geol. Scis 10, 1-260. (Chinese, English summary). XING YUSHENG & YUE ZH AO, 1984. (The Sinian- Cambrian boundary in southwestern part of Shaanxi). Bull. Inst. Geol., Chinese Acad. geol. Scis,111-125. (Chinese). YANG XIANHE & HE TINGGUI, 1984.(New small shelly fossils from Lower Cambrian Meishucun Stage of Nanjiang area, northern Sichuan). Pro! Pap. Strat. Palaeont. 1 3, 35-4 7. (Chinese,English . summary). YANG XIANHE, HE YUANXIANG & DENG SHOUHE, 1983. (On the Sinian-Cambrian bound� ary and the small shelly fossil assemblages in Nan jiang area, Sichuan). Bull. Chengdu Inst. Geol. Miner. Res. 4, 91-1 1 0(Chinese,English summary). YIN GONGZHENG & Ll SHENCHI,1978. Trilobita. In Atlas of the palaeontology of southwestern China, Guizhou Province. Part 1. Cambrian Devonian. Geological Publishing House, Beijing, 385-830. (Chinese). YIN JICHENG, DING LlANFENG, HE TINGGUI, Ll SHILlN & SHEN LlJUAN, 1980. (The palaeon tology and sedimentary environment of the Sinian system in Emei-Ganluo area, Sichuan). Geological College of Chengdu, Chengdu, 231p. (Chinese, English summary). YIN GONGZHENG,WANG YANZEN, & QIAN YI, 1982. (A preliminary study of the Sinian-Cambrian boundary in Guizhou province). J. Strat. 6, 286293. (Chinese). YOUNGS, B.C. & MOORECROFT, E., 1982. The petroleum potential of the eastern Arrowie Basin and Frome Embayment. APEA J. 22, 82-101. YU WEN, 1979. (Earliest Cambrian.monoplac ophorans and gastropods from western Hubei with biostratigraphical significance).Acta palaeont. sin. 18, 233-270. (Chinese, English summary). YU WEN, 1986. Lower Cambrian univalved molluscs from Kuruktag, Xinjiang. Acta palaeont. sin. 25, 10-16.(Chinese,English summary). YU WEN, 1987. Yangtze micromolluscan fauna in Yangtze region of China with notes on the Precambrian-Cambrian boundary. In Stratigraphy and palaeontology of systemic boundaries in China. Precambrian--Cambrian boundary 1. Nanj ing Univ. Press, Nanjing, 19-344.(Chinese). YUAN KEXING & ZHANG SENGUI, 1983. (Dis covery of the Tommotia fauna in SW China). Acta palaeont. sin. 22, 31-40. (Chinese, English sum mary). YUE ZHAO, 1986. Microstructure and systematic position of Olivooides (Porifera). Bull. Inst. Geol., Chinese Acad. geol. Scis 14, 147-162. (Chinese, English Summary). YUE ZHAO, 1987. (The discovery of Tannuolina and
Lapworthella from Lower Cambrian in Meishucun (Yunnan) and Maidiping (Sichuan) sections). Pro! Pap. Strat. Pa/aeont. 16, 173-180. (Chinese, English summary). ZHANG LUYJ, 1986. (A discovery and preliminary study of the late stage of late Gaojiashan biota from Sinian in Ningqiang County, Shaanxi). Bull. Xian Inst. Geol. miner. Res. 13,67-88. (Chinese,English summary). ZHANG WENTANG, 1950. Report of the meeting of the Palaeontological Society of China. Newsletter of the Geological Society of China 2(1), 10 . ZHANG WENTANG, 1953. Some Lower Cambrian trilobites from western Hupei. Acta palaeont. sin. 1,121-149. ZHANG WENTANG, 1957. Cambrian and Or dovician stratigraphy of the gorge district of the Yangtse,Hupeh. Kexue Tongbao, Academia Sinica 1957(5), 145. ZHANG WENTANG, 1962. On the genus Eored lichia. Acta palaeont. sin. 10, 36-44 .. ZHANG WENTANG, 1964. The boundary between the Lower and Middle Cambrian with description of some ptychopariid trilobites.Science Press, Beij ing, 38p.(Chinese). ZHANG WENTANG, 1966. On the classification of Redlichiacea, with description of new families and new genera. Acta palaeollt. sill. 14, 135-184. (Chinese, English summary). ZHANG WENTANG, 1985. Current biostratigraphic scheme of the Chinese Cambrian. Palaeont. cathayana 2, 73-75. ZHANG,WENTANG & JELL,P.A., 1987.Cambrian trilobites of north China. Science Press, Beijing, 1459. ZHANG WENTANG, LU YANHOU,ZHU ZHAOL ING, QIAN YI, LlN, H., ZHOU ZHIYI, ZHANG SANGUI & YUAN, JINLIANG, 1980. Cambrian trilobite faunas of Southwestern China. Palaeont. sin. ser. B, 16, 1-497. (Chinese with English sum mary). ZHANG XIGUANG, 1987. Moult stages and dimor phism of Early Cambrian bradoriidsJrom Xichuan, Henan, China. Alcheringa 11 1 19 ZHONG HUA [CHEN MENGEJ, 1977. Preliminary study on the ancient fauna of South China and its stratigraphic significance. Sciellt. geol. sin. 1977, 118- 128. (Chinese, English summary). ZHOU BENHE & XIAO LlGONG, 1984a. Early Cambrian monoplacophorans and gastropods from Huainan and Huoqiu Counties, Anhui Province. Prof Pap. Stratig. Palaeont. 13, 1 37-140. (Chinese). ZHOU BENHE & XJAO LlGONG, 1984b. Early Cambrian Hyolitha from Huainan and Huoqiu County in Anhui Province. Pro! Pap. Stratig. Palaeollt. 13, 15G-151.(Chinese) ZHU ZHAOLlNG & UN TIANMI, 1978. Some Mid dle Cambrian trilobites from Yuxian, Hainan Is land. Acta palaeont. sill. 17, 439-444. (Chinese, English summary). ZHURAVLEVA, LT., 1986. Radiocyathids. In Problematic fossil taxa, A. Hoffman & M.H. Nitecki, eds, Oxford University Press, New York, 35-44. ,
-
.
EARLY CAMBRIAN FOSSILS, S. AUST.
ZHURAVLEVA, I.T. & KORDEH, K.B., 1955. Nak hodka gubki Chancelloria Wa1cott v otlozheniyakh nizhnego kembriya Sibiri. (Discovery of the sponge Chancellorill Wa1cott in the Lower Cambrian deposits of Siberia). Dokl. Akad. Nauk. SSSR 104, 474-477.(Russian).
361
ZHURAVLEVA, I.T., ZADOROZHNAYA, N.M., OSADCHAYA, D.V., POKROVSKAYA, N.V., RODIONOVA, N.M. & FONIN, V.D., 1967.
Fauna nizhnego kembriya Tuvy. (Fauna of the Lower Cambrian of Tuva). Sib. otdel. Inst. Geol. Geofiz., Akad. nauk SSSR, Izdatelstvo, Moscow, 1- 181. (Russian)
APPENDIX Maps referred to are;1:100,000 topographic series: Wakefield sheet 6529 (2nd ed.) Maitland sheet 6429 (1st ed.) Stansbury = sheet 6428 (1st ed.) Quom sheet 6533 (1st ed.) =
=
=
1:63360 (or 1 mile) series of the South Australian State Geological Atlas:Oraparinna = sheet 670 Blinman = sheet 660 Copley = sheet 686 1 :5 0,000 topographic series of the South Australian Department of Lands:Copley sheet 65316-1 (2nd ed.) 1982. =
Key to abbreviations used: GR Grid reference (east, north) NMV Museum of Victoria UNE University of New England South Australian Department of Mines and Energy localities are quoted in the form of a 4-digit number referring to the 1:100,000 topographic sheet, followed by 'RS' indicating a rock sample, followed by a locality number that is plotted on a set of master maps held by the department. LOCALITIES UNEL1760. Trilobite-bearing bed near small culvert on north side of Port Wakefield-Kulpara road, 2.4 km east of Kulpara, northern Yorke Peninsula (Hummocks section); = NMVPL71, 6529RS106, a n d U N E L 1 8 6 0 c . A t 34°0 4 ' S , 1 3 8°05'E; GR286263 on Wakefield. Abadiella huoi Zone, Parara Lst. UNEL1761. Lowermost 1-2 m of Parara Lst. in gully on west side of Ardrossan - Port Vincent road, 5 km SSW of Ardrossan, Yorke Peninsula (Horse Gully section); = NMVPL76, 6429RS106, and UNEL1856. 34°28'S, 137°53'E; GR654824 on Maitland. Abadiella huoi Zone, Parara Lst.
UNELI762. Main outcrop of Parara Lst. in Horse Gully section (see UNEL1761), just above second major break in slope north of gully, and c. 18 m stratigraphically above the base of Parara Lst.; = NMVPL77, UNEL1854, and 6429RS108-9. Pararaia tatei Zone, Parara Lst. UNEL1762A. Highest outcrops in Horse Gully sec tion (see UNEL1761), on hill to north of gully; =6429RS112-114. Pararaia tatei Zone,Parara Lst. UNEL1763A. Random sample from spoil in quarry about 1 km SSW of Curramulka, Yorke Peninsula (Curramulka Quarry section). 34°42'S, 137°42'E; GR475563 on Stansbury. Abadiella huoi Zone, Parara Lst. UNEL1763B. Trilobite bed in Curramulka Quarry section (see UNEL1763A), on south wall of quarry just below change in slope; c. 4m below UNEL1850 and =UNEL1846 and NMVPL78. Abadiella huoi Zone, Parara Lst. UNEL1763C. Phosphatic bed in Curramulka Quarry s e c t i o n ( s e e U N E L I 7 6 3 A ) , c. 5m a b o v e UNEL1763B, a n d 1 . 5 m below UNEL1850. =UNEL1848. Abadiella huoi Zone, Parara Lst. UNEL1764. Thin nodular carbonate bed on ridge c. 0.3km north of Bunyeroo Gorge and c. lOOm east of vermin-proof fence opposite first hill north of B un y e r o o C r e e k , cent ral F l inders R a nges; =NMVPL80. 31°2 4 '30"S, 138°31 ' 4 0"E o n Oraparinna. P a r a r a i a ja n e a e Zone, lower Oraparinna Shale. UNEL1766A. Red limestone horizon in upper part of Ajax Lst. in creek bed on north side of Mt ScoU Range, northern Flinders Ranges. About 0.7 km SE of UNEL1874. 30037'S, 138°22'E; GR470100 on Copley 1 :50 000. Pararaia tatei Zone, Ajax Lst. UNEL176 6B. Trilobite bed beneath small ar chaeocyath bioherm in upper part of Ajax Lst. in creek section on north side of Mt ScoU Range, northern Flinders Ranges. About 0.7 km SE of U N E L 1 8 7 4 a n d = U N E L I 8 7 7 . GR as f o r UNELI766A. Pararaia tatei Zone, Ajax Lst. UNEL1766C. Top of ridge along strike to SE of UNEL1766A,B; = UNEL1876. 30037'S, 138°22'E; GR471100 on Copley 1 :50,000. Pararaia tatei Zone, Ajax Lst. UNEL1778. Silicified limestone containing Pelagiel la, 1- 2 m above the dolomitized part of section, and c. 110m above the base of Ajax Lst., middle of Ajax Lst. in creek section on north side of Mt Scott Range, 3.5 km WSW of Aroona Dam wall, northern Flinders Ranges (section M, Gravestock, 1984, fig.
362
STEFAN BENGTSON et aL
2); = UNEL1865. 30035.5'S, 138°20'E; GR439122 on Copley 1:50,000. Ajax Lst. UNEL1779. Interbedded limestones and siltstones with abundant trilobite fragments in same creek section as, and c. 60m above UNEL1778; = U N E L 1 8 6 6 , 1 8 6 9 . 3 003 5 . 5 'S, 1 3 8°20'E; GR439122 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lst. UNEL1822. Silicified trilobite horizon in same creek section as, and c. ] 00 m above UNEL 1778; = UNEL1871, c. NMVPL1503. 30° 35.5'S, 138° 20'E; GR438125 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lst. UNEL1833. Massive red limestone with Pojetaia and Chancelloria in same creek section as, and c. 160 m above UNEL1778; =UNEL1873, NMVPL83. 30035.5'S, 138° 20'E; GR438125 on Copley 1:50,000. Pararaia tatei Zone, upper Ajax Lst. UNEL1845. Limestone c. lOm above quarry floor and c. 6m below UNEL1763B. Curramulka Quarry sec tion (see UNEL1763A), Abadiella huoi Zone, Parara Lst. UNEL1846. Equivalent to UNEL1763B. Curramulka Quarry section (see UNEL1763A). Abadiella huoi Zone, Parara Lsl. UNEL1847. Limestone c. 2.3m above UNEL 1763C. Curramulka Quarry section (see UNEL1763A). Abadiella huoi Zone, Parara Lst. UNEL1848. Limestone c. 2.5m above UNEL1763B; =UNEL1763C. Curramulka Quarry section (see UNEL1763A). Abadiella huoi Zone, Parara Lst.
UNEL1860B. Small outcrop of limestone c. 1m above UNEL1860A at Hummocks section. GR as for UNEL1760. Abadiella huoi Zone, Parara Lst. UNEL1860C. Equivalent to UNEL1760. Hummocks section, Abadiella huoi Zone, Parara Lst. UNEL1862. West side of Ross River c. 1 km SW of Ross River Chalet, 62km E of Alice Springs, North ern Territory. 23° 36'S., 134° 30'E, Todd River Dolomite. UNEL1862A. 83.2m above base of Todd River Dolomite, c. 2 m below loc. 59 of Laurie (1986) on Kennard's section (850) Undoolya 1:100,000 map sheel. UNEL1862B. About 78.2 m above base of Todd River Dolomite and 5 m below UNEL1862A (glauconitic with obvious fossils). UNEL1863A. Halfway up southern face of the south western and larger of two hills west of a N--S fence, C. 6km N 60"E of Phillipson No.7 Bore, about 70km SE of A l i c e S p r i n g s , N o r t h e r n T e r r i t o r y. 134°18.6'E, 24°13'S. Todd River Dolomite. UNEL1865. Equivalent to UNEL1778. Mt Scot! Range. UNEL1866. Bed with silicified trilobites and archaeo cyaths c. 35 m above UNEL1778 in same creek section. It is C. 25 m E of point where creek first turns to NNE after following strike of bedding. 30035.5'S, 138°20'E; GR4 38123 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lst.
on road from Kulpara to Port Wakefield, c. 9 km east of Kulpara (Hummocks section), c. 2m below
wall and is lateral equivalent of beds immediately above UNEL1779. 30037'S, ] 38°22'E; GR46510J on Copley 1 :50,000. Pararaia tatei Zone, Ajax Lst. UNEL1876. Approximately = UNEL1766C.
UNEL1849. Lst. C. 3m above UNEL1763B. Cur ramulka Quarry section (see UNEL1763A). Abadiella huoi Zone, Parara Lst. UNEL1850. Limestone c. 4m above UNEL1763B; = UNEL1763C. Curramulka Quarry section (see UNEL1763A). Abadiella huoi Zone, Parara Lst. UNEL1851. Limestone c. O.4m above UNEL1850 and 4.4m above UNEL1763B. Curramulka Quarry sec tion (see UNEL1763A). Abadiella huoi Zone, Parara Lst. UNEL1852. Limestone from fourth highest outcrop of Horse Gully section (see UNEL1761); =6429 RS111. Pararaia tatei Zone, Parara Lsl. UNEL1853. Limestone from fifth highest outcrop at Horse Gully section (see UNEL1761); =6429 RSII0). Pararaia tatei Zone, Parara Lst. UNEL1854. Equivalent to UNEL1762. Horse Gully section, Pararaia tatei Zone, Parara Lsl. UNEL1855. Limestone from middle of Horse Gully section (see L176]); c. Bm above base of Parara Lsl. (Fig. 4). Abadiella huoi Zone, Parara Lsl. UNEL1856. Equivalent to UNEL1761. Horse Gully section, Abadiella huoi Zone, Parara Lst. UNEL1857. Uppermost Kulpara Lst. at Horse Gully section (see UNEL176I), just below first red band in section; =6429RS105. UNEL1858. Kulpara Lst. c. 7.5m below base of Parara Lst. in Horse Gully section (see UNEL1761). UNEL1859. Kulpara Lst. from c. 20m below base of Parara Lst. in Horse Gully section (see UNEL 176]), from exposed base of section; 6429RSlOl. UNEL1860A. Trilobite-bearing bed near small culvert
UNEL1860C. GR as for UNEL1760. Abadiella
huoi Zone, Parara Lst.
UNEL1867. Limestone from same creek section as UNEL1778, from point at which creek first turns to NNE after following strike of bedding; =UNEL 1868, and approximate lateral equivalent of UNEL 1779. 30035.5'S, 138°20'E; GR438123 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lst. UNEL1868. Near UNEL1867 and also an ap proximate lateral equivalent of UNEL1779. Mt Scot! Range, Abadiella huoi Zone, Ajax Lsl. UNEL1869. Limestone from section near same creek as UNEL1778, C. 40m above UNEL1778 and C. 25m E of point where creek first turns to NNE after following strike of b e d d i n g ; c . 5m above UNEL1866. 30035.5'S, 138°20'E; GR438123 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lsl. UNEL1870. Lsl. from section near same creek as UNEL1778, C. 30 m above UNEL1779, and 75 m NW of U N EL1 8 6 7 . 3 0° 3 5 . 5 ' S, ] 38°20'E; GR438125 on Copley 1:50,000. Abadiella huoi Zone, Ajax Lst. UNEL1871. Equivalent to UNEL1822. Mt Scol! Range. UNEL1872. Limestone from same creek section as UNEL1778, C. 25m above and 55 m NW of UNEL1822. 30035.5'S, 138°20'E; GR438125 on Copley 1 :50,000. Abadiella huoi Zone, Ajax Lst. UNEL1873. Equivalent to UNEL1833. UNEL1874. Upper part of Ajax Lsl. on ridge-top in Section J of Gravestock (1984, fig. 2), Ml. Scot! Ra. Exactly 3 km due south of west end of Aroona Dam
EARLY CAMBRIAN FOSSILS, S. AUST.
UNELl877. Approximately = UNELl766B (fallen block in same creek). Mt Scott Range, Pararaia tate; Zone, Ajax Lst. NMVPL71. In small culvert on north side of Port Wakefield to Kulpara Road, Hummocks Section. Coming from east it is on second curve to left as road rises up over first ridge and straightens up after first swing to south. =9529RSI04-106, UNE1760, 186Oc. GR285264 on Wakefield. Abadiella huo; Zone, low inParara Lst. NMVPL73. In gutter on north side ofPort Wakefield to Kulpara Road, Hummocks Section. Coming from east it is just beyond first curve to south and just west of electricity substation. =6529RS 112,113. GR287263 on Wakefield. Pararaia tatei Zone,Parara Lst. NMVPL76. Silicified horizon in 2m above reddened limestone horizon 500m from main road in north side of gully (Horse Gully section) 4km south of Ardrossan, Yor k e Peninsula . =UNELI761. GR654824 on Maitland. Abadiella huoi Zone, Parara Lst. NMVPL77. Prominently outcropping horizon 5m thick with base 15m above reddened horizon in Horse Gully section (see NMVPL76). GR655825 on Maitland. Pararaia tate; Zone, Parara Lst. NMVPL78. 10-15m above floor on southern face of quarry on northern face of steep rise lkm SSW of Curramulka, Yorke Peninsula. GR475563 on Stansbury. Abadiella huoi Zone,Parara Lst. NMVPLSO. Thin nodular limestones in shales in gul lies and on ridges c. 0.3km north of western end of Bunyeroo Gorge, 75 km north of Hawker. 31°24' 30"S, 138°31'40"E. =UNELl764 on Oraparinna. Pararaia janeae Zone, basal Oraparinna Shale. NMVPLS3. Red limestone 30m from eastern end of first creek gorge lkm southwest of gate on track 1 km west of turnoff on road 2.5km southwest from Aroona Dam, Mount Scolt Range. 30036'38"S, 138°22'2"E on Copley 1:63360. Pararaia tate; Zone, Ajax Lst. NMVPLS7. In steep left bank of small stream lOOm south of the Wirrealpa to Blinman road 5km west of Old Wirrealpa Mine turnoff on western side of diapiric structure, c. 12km northwest of Wirrealpa. 31°5'20"S, 138°51' E on Blinman. Pararaia janeae Zone, Oraparinna Shale. NMVPLS8. Thin oolitic bed in creek bed just beneath 2m stromatolite bed lOOm north ofWirrealpa Mine turnoff on Wirrealpa to Blinman Road c. 7km northwest of Wirrealpa. 31°5'45"S, 138°53'54"E on Blinman. Wirrealpa Lst. NMVPL89. Thin flaggy steel grey limestone unit c. lOOm west of road 500m north of Red Tank Well 6 k m n or t h w es t of W i r r e a l p a . 3 1°6'3O"S, 138°54'18"E on Blinman. Moodlatana Formation. NMVPL94. In sharp gully near rock wall at fence on south side of Port Wakefield to Kulpara Road at eastern end of first curve to south on Hummocks Section. GR288262 on Wakefield. Pararaia tate; Zone,Parara Lst. NMVPL95. At mouth of small cave in shallow depres sion on top of broad ridge 2.4km southwest of Curramulka, Yorke Peninsula. GR463552 on S tansbury. Pararaia tatei Zone,Parara Lst.
363
NMVPL96. Horizon with numerous phosphatic nodules and surface silicified trilobite exoskeletons in muddy limestone on north side ofPort Wakefield to Kulpara Road (Hummocks section). Coming from east it is on curve back to north just beyond N M V P L 7 3 . = 6 5 2 9R S I 0 9 . G R 2 8 6 2 6 3 on Wakefield. Abadiella huoi Zone,Parara Lst. NMVPL99. A channel fill horizon in dark limestone 120m west of the windmill and tank at the western end of Bunyeroo Gorge on south side of stream. 31°24' 45"S, 138°31'36 "E on Oraparinna. Pararaia bunyerooensis Zone,Parara Lst. NMVPLlOO. White sugary limestone float o n southern slope of main ridge running east from Wirrealpa Mine, 7km northwest of Wirrealpa. 31°4'35"S, 138°55'10"E on Blinman. Wilkawillina Lst. NMVPL1498 In coarse skeletal grainstone in the first 10m above a thin reddened horizon on the northern side of a creek gully on northern side of the main r i d g e fun n i n g e a s t f r o m W i r r e a l p a M i n e . 31°4'22"S, 138°55'12"E on Blinman. Pararaia tatei Zone, Wilkawillina Lst. NMVPL1499 Coarse skeletal grainstone with many archaeocyathids near top of ridge running east from Wirrealpa Lead Mine, 1.1km east of mine, 7km northwest of Wirrealpa. 31°4'28"S, 138°55'18"E on Blinman. (?Pararaia janeae Zone), Wilkawil lina Lst. NMVPL1503 Silicified horizon in creek section on north side of Mt. Scott Ra., 2,75 km WSW of Aroona Dam. (section M of Gravestock (1984, fig. 2) in central Mount Scott Range. = UNELl822, 1871. 30035'14"S, 1380 19'57"E on C o p le y 1 :63360. Abadiella huoi Zone, Ajax Lst. NMVPLl509. Just beneath limestone conglomerate high on steep ridge 300m northwest of Old Wirreal pa Springs on old track to Point Well Homestead, llkm northwest of Wirrealpa. 31"3'30"S, 138° 53 '20"E on Blinman. Abadiella huoi Zone, Wilkawillina Lst. NMVPL1513. Black limestone on track towards top of main north- south ridge across section G of Gravestock (1984, fig.l) east of Wilkawillina Gorge. 31°16'17"S, 138°53'31"E on Oraparinna. Pararaia bunyerooensis Zone, c. 300m above base ofParara Lst.
Localities NMVPL1580, 1584 and 1585 are in the thin Parara Lst. unit exposed in the syncline just north of Mount Ragless. See WiIIochra, sheet 746, of the State Geological Atlas 1 mile Series, first edn 1962.
NMVPL1580. On top of ridge just east of small cap of duricrust nearly lkm west of WiIlochra Creek and 4km north of Mount Ragless. GR271463 on Quorn. Pararaia tatei Zone,Parara Lst. NMVPL1584. 1-2m above prominent ripple-marked bed in intraformational breccia with rounded lime stone c1asts on western limb of syncline 200m south of two small caps of duricrust, 3.5km north of Mount Ragless. GR265456 on Quorn. Pararaia tatei Zone,Parara Lst. NMVPL1585. 15-25m above same ripple-marked bed as mentioned in NMVPL1584. GR264456 on
364
STEFAN BENGTSON et aL
Quom. Pararaia tatei Zone, Parara ut.
The next three localities are in a short section of coarse clastics with interbedded fine shales and limestones. lenkins (1990, fig. 9) interpreted these fossil horizons as belonging to the upper Parara Limestone but our interpretation and that of the geological map of the area (Oraparinna 1:63,360 sheet) places these horizons within the base of the Oraparinna Shale. NMVPLl588. In interbedded shales and limestones in low south bank of creek just west of western entrance to Bunyeroo Gorge, in section extending west from windmill and tank c. 50m above NMV PL99. 31°Z4'4Z"S, 138°31'3Z"E on Oraparinna. Pararaia janeae Zone, Oraparinna Shale. NMVPLl589. Im below NMVPLl588 in same section. Zone, Oraparinna Shale. NMVPLl590. 2m below NMVPLl589 in same sec tion. Pararaiajaneae Zone, Oraparinna Shale. NMVPLl591. Dark limestone I5m above base of formation 25m east of sharp turn to east in first left bank tributary on top of steep cliff in creek along which type section is measured Le. section E of Gravestock (1984, fig.1). 138°53'25" E on Oraparinna. Pararaia tatei Zone, Parara ut. NMVPL 1592. Limestone nodules near top o f Oraparinna Shale just below Edeowie Lst. in type section on western slope of prominent but low strike ridge. 31°15'51 MS, 138°53'53"E on Oraparinna. Pararaia janeae Zone, Oraparinna Shale. NMVPLl593. Prominently outcropping silicified 2m limestone unit in deep gully on eastern side of high
east of Wilkawillina Gorge (presumably the 'limestone band 3 feet thick 250 feet below the top of the formation' mentioned by Daily (1956, p.114)whtch contained his faunal assemblage 8). 1 31°15 50"S, 1 3 8°54'24"E on O r a p a r i n n a . Pararaia bunyerooensis Parara ut. NMVPL1594. In coarse grainstone at first prominent branching of creek at top of steep slope section i.e. section E of Gravesfrom west in Zm below base of Parara ut. tock (1984, on Oraparinna. Zone, 31°15'50"8, Wilkawillina Lst. NMVPLl595. ut. nodules in shale where old track is cut into southern creek bank at western end of Bunyeroo Gorge, 40-50m above NMVPL1588. 31°24'40"S, 138°31 ' 3 0" E on O r a p a r i n n a . Oraparinna Shale. Pararaia janeae and wave-cut platform just NMVPLlS96. In sea Gully, 1.5km west of White east of mouth of of Kangaroo Island. [Conway Point on north Morris & Jenkins (1985) quoted the location as 3km west of White Point giving Daily et al., 1979, fig. 8 as a reference; taking the scale given on that figure the distance indicated west of White Point is ap proximately l.5km]. Pararaia janeae Zone, Emu Bay Shale. NMVPL1599. Shale with interbedded minor lime stones and limestone nodules in creek gully just west of old track (i.e. as marked on Blinman), 1.3km west of old Wirrealpa Sprin�s, 11.3km northwest ofWirrealpa. 31"3'30"S, 138 52'30"E on Blinman. Pararaia janeae Zone, Oraparinna Shale.
